Linguistic groups have evolved from ancient Persian to present-day Persian dialects, in which phonological change and evolution are one of the most important changes in this article. It attempts to determine the phonological and semantic evolution in the book Behaghi's history is to be portrayed as one of the prominent Khorasani style prose in the fifth century. Due to the close proximity of Beihaqi's history to the Middle Persian (Pahlavi), many of the phonetic features of the Pahlavi language have been preserved in themselves, and have come to terms with such words as, obvious, paternity, and ... without any changes. The methodology used in this research was descriptive-librarian. Phonological variations in terms of: reduction, discretion, increase, integrity, and integration have shown that the greatest process of this change has been straightforward. In the evolution of the meaning of the verse in this article, the words will encounter a number of evolutionary situations. They are abandoned or, in addition to the meaning of the past, have taken a new meaning. In the semantic transformation of sentences, they are often used in their unrealistic and conditional sense and in sentences They have come to the scene

We live in a world of language and we communicate with each other using language (Fromkin et al., 2007). Deafness occurs when a person cannot understand speech through hearing, even when the sound is amplified. The degree of hearing loss is measured according to the sensitivity of deaf people’s ears to the sounds (Ganji, 2017) and then those people are asked to use hearing aids or do cochlear implantation surgery (Ebrahimi, 2006). Children have the opportunity to hear others’ speech during normal speech development while children with hearing impairment lose much of the auditory input, which may hinder speech development (Tseng et al., 2011 as cited in Serry and Blamey, 1999; Blamey et al., 2001; Peng et al., 2004; Bouchard et al., 2007). Different factors will affect speech development. One of these factors is DISABILITY, any disorder in hearing will affect speech and subsequently will cause problems in communication (Amiri et al., 2014). Some speech characteristics of children with hearing loss are different from each other and different from normally hearing children (Kord et al., 2012). GENDER is another factor affecting speech. While analyzing vowels produced by Azari speakers, Mirahadi et al. (2018) proved that men produce some vowels different from women. Vowel space is a vowel quadrilateral which is used to shows the first and the second formants. Phoneticians put vowels in the vowel space according to their position in the oral cavity, which was first introduced by Essner (1947) and Joos (1948) (as cited in Harrington & Cassidy, 1999). The first formant will increase as we go down the vowel space, it shows highness of tongue while producing vowels in the oral cavity. The second formant shows anterior or posterior position of tongue in the process of production of vowels in the oral cavity and will increase as we go to the left side of the vowel space (Hayward, 2013: 227, 228 & 502). The present study aims to compare the vowel space of hearing aided, cochlear implanted, and normally hearing children, with DISABILITY and GENDER as factors, in order to investigate the difference between the vowels produced by these children (Their average age was 10 years and 4 months and their participation in the study was optional, after getting permission from their parents.) and find out more effective hearing aid tools among two groups of children with DISABILITY (They did not have any mental or physical problems except hearing impairment and took part in language therapy classes for about 450 hours.), the group which makes vowels similar to normally hearing children will prove the effectivity of the hearing aid tools. So, the results will be useful for language therapists while helping children learn how to pronounce vowels. Therefore, the participants, 5 girls and 5 boys in each group, were asked to repeat thirty-six CVC framed words. Each word consists of one of the stops [p, b, t, d, k, g] in the onset and offset of the pattern and one of the Persian vowels [æ, e, o, a, i, u] in the center. Then the words were recorded using a Shure microphone in PRAAT software. After that, the first and the second formants of each vowel were measured and by using SPSS software the data was analyzed. The results showed that the effect of DISABILITY on the first formant of vowels [æ, a, i, u] and the second formant of vowels [a, e, o, u] was significantly different (p < 0.050). The results of a Post Hoc Bonferroni test showed that children with DISABILITY produced vowels [u, i, e, ᴂ] in a lower place in the vowel space comparing to normally hearings. Cochlear implanted children produced vowel [a] in a lower place and vowel [o] in a higher place in the vowel space comparing to normally hearings. Hearing aided children produced vowel [a] in a higher place in the vowel space comparing to normally hearings. All vowels in cochlear implanted children and vowels [ᴂ, a, e, i, u] in hearing aided children were produced in an anterior place in the vowel space comparing to normally hearings. The results also proved that the effect of GENDER on the first formant of vowel [a] and the second formant of vowel [i] was significantly different (p < 0.050). The results of a Post Hoc Bonferroni test revealed that the mean of the first formant of vowel [a] in girls was more than boys and the mean of the second formant of vowel [i] in girls was less than boys. It is also important to mention that hearing aided children had the smallest vowel space among three groups of participants while the vowel space of cochlear implanted children was not so different from the vowel space of normally hearings. So, language therapists have to try more to teach vowels to the children who use hearing aids comparing to the children who are cochlear implanted.

In many Iranian languages and dialects, [a] is raised to [e] in a process other than vowel harmony or assimilation to a neighboring consonant. For instance, in Delvari [a] raises to [e] when a word such as [dar] ‘door’ appears in its plural form [der-ɑ] ‘doors’. In this case, vowel raising is clearly not a consequence of vowel harmony or assimilation to an adjacent consonant. Previous research on these languages and dialects have seen this type of vowel raising process as being dependent on the number of syllables, the position of the syllable in the word, and stress. A closer look at relevant data shows that this process is rather sensitive to whether the syllable in which [a] occurs is closed or open. Data from various Iranian languages and dialects shows that the low vowel [a] is raised to [e] when the closed syllable in which it occurs becomes open as the result of the deletion of final consonants or their re-syllabification in morphological processes. The deletion of word-final consonants has led to the raising of [a] to [e] and the neutralization of contrast between these two vowels in final position in the development of Middle Persian to Modern Persian. Even the free variation observed between [a] and [e] in the pronunciation of many words seems to be due to the fact that [a] is preferred in closed and [e] is preferred in open syllables. An acoustic study of Persian vowels in word-final closed and open syllables also shows the raising of the whole vowel space and significantly the raising of [a] in open syllables. This feature is very similar to what is observed in tense-lax vowel systems in which lax (more open) vowels tend to occur in closed syllables and tense (more closed) vowels are preferred in open syllables.

Formant structure is an important feature of vowels in any language. The formant structure of any vowel can be a function of gender. This study investigated the formant structure of six Persian vowels used in the speech of Turkish speakers aged 18-28 years old.
This is a descriptive-analytic cross-sectional study. A total of 30 male (N=15) and female (N= 15) 18-28 year old participants were recruited from among Turkish speaking students studying at Iranian University of Medical Sciences. The fundamental frequency and three first formants of each of six Persian vowels were recorded by Praat software. Independent samples-t test and Mann U Whitney were used to analyze the data.
Among male participants, the lowest fundamental frequency was related to /æ/ vowel with a mean of 120 Hz, the highest being /i/ vowel with a mean of 128 Hz. The lowest first formant was related to /i/ vowel with a mean of 280 Hz, the highest being /æ/ vowel with mean of 693 Hz. The highest second formant was related to /o/ vowel with a mean of 931 Hz, the lowest being /i/ vowel with mean of 2135 Hz. The lowest third formant was related to /æ/ vowel with mean of 2554 Hz, the highest being /i/ vowel with mean of 2927 Hz. Among the female participants, the lowest fundamental frequency was related to /æ/ vowel with mean of 219 Hz, the highest being /i/ vowel with mean of 249 Hz. The lowest first formant was related to /i/ vowel with mean of 348 Hz, the highest being /æ/ vowel with mean of 943 Hz. The lowest second formant was related to /u/ vowel with mean of 771 Hz, the highest being /i/ vowel with mean of 2686 Hz. The lowest third formant was related to /æ/ vowel with mean of 2815 Hz, the highest being /i/ vowel with mean of 3303 Hz. All the differences between male and female participants were significant except for the first and third formant in /u/ vowel, second formant in /o/ vowel and third formant in /a/ vowel (p It can be concluded gender is not only a factor for a differences of fundamental frequency, but it also can account for differences in vowel space of Persian vowels in the speech Turkish male and female speakers. It seems that the significant greater amount of fundamental frequency of all of vowels in females can be the result of smaller dimensions of larynx, and smaller length and mass of vocal tract, though part of this difference may be a function of other factors such as language or dialect. The significant greater amount of first formant of female participants shows the higher position of tongue in females during production of the vowels. Reduction in second formant with more posterior vowels shows the smaller distance between the narrowest place of articulators and larynx. Vowel space in female participants was greater than that in males, obviously in front vowels. Therefore, it seems necessary to replicate this study in some other languages or dialects for closer study of gender's effect and other factors such as language or dialect.

Down syndrome (hereafter DS) is a chromosomal condition caused by the presence of all or part of a third copy of chromosome 21. People with DS may have a variety of intellectual disabilities, a characteristic facial appearance and weak muscle tone. In addition, a global delay that affects their motor development, cognition, communication and language is often reported. This study aims to investigate and compare vowel spaces of healthy and DS children. This research is quantitative and to investigate vowel spaces of participants, twelve subjects (6 healthy children with the average age of 8 and 6 DS children with the average age of 10) attended the research project. The data were 36 monosyllabic (CVC) words and for each of them, the codas and onsets were occupied by similar voiced and voiceless Persian stops. The acoustic data were recorded in a soundproof chamber and the subjects’ production was recorded using SHURE® microphone (SM81 Condenser) placed at the mouth level. Each speech sample was segmented and analyzed acoustically using Praat® speech analysis software (Version 5.2.24). Making a text grid, it was possible to analyze both sound waves and spectrograms simultaneously, securing reliable analyses. Therefore, using PRAAT script, first formant frequency (F1) and second formant frequency (F2) of all the Persian vowels were measured for all the participants. In the next step, repeated measure ANOVA and SPSS (version 17) were performed to investigate differences between vowels of all subjects. The level of significance was α: 0.05. Thus, the confidence interval would be 95%. If the p-value of the repeated measure ANOVA was less than 0.05, post-hoc Bonferroni test would be employed to analyze the dependent variables. Statistical information on mean F1 of vowels shows that F1 of [ɑ, æ, o] in healthy children is more than that in children with DS. This result indicates that these vowels are articulated in a higher position in subjects with DS. From the other hand, mean F1 of [u, i, e] in healthy children is more than that of children with DS. It can be concluded that in children with DS, these vowels are articulated in a lower position. Analyzing statistical information on mean F2 of vowels in subjects with DS indicates that F2 of [æ, i, e] is less than those in healthy children. In other words, these vowels are articulated in a more back position in these participants. Also, analyzing F2 of [ɑ, u, o] in DS children shows that these vowels are articulated in a more front position. Another part of this research is dedicated to analytic statistics of vowels. It was hypothesized that the effect of DS on F1 and F2 of vowels is significant. This hypothesis is partially supported by the findings. The results indicate that there is no significant difference between F1 of all Persian vowels [æ, e, o, ɑ, u, i] in the two groups of subjects. Nevertheless, it is worth noting that the difference between F2 of all Persian vowels except [ɑ] is significant between healthy and DS children. All in all, these results support the fact that formant values are more centralized for children with DS, which means a reduced vowel space area. Consequently, it can be concluded that, in DS children, structural features of oral cavity, like smaller oral orifice, narrower but not higher palatal curve and shorter vocal cords have an effect on formant structure of vowels.

The present study investigates and compares the process of vowel shortening in Persian and Central Kurdish languages based on optimization theory. Since almost the same phonological processes occur in co-type languages, despite the long vowels in Persian and Kurdish, it is expected that vowel shortening process will occur in these languages. In the present study, Phonological analysis of data showed that vowel shortening occurs in high and low vowels in both Persian and Kurdish. In Persian, three long vowels /i, u, ɑ/ and in Kurdish, two long vowels /i, ɑ/ undergo vowel shortening process. Depending on the phonetic context, in the both languages the vowel /ɑ/ can only be reduced to two short vowels /e/ and /æ/ in Persian and two short vowels /ə/ and /æ/ in Kurdish. In Persian, the number and variety of context in which long vowels are shortened is more than in Kurdish. Optimality analysis also showed that the type and order of final constraints and marking constraints on the shortening of long vowels /ɑ/ and /i/ are the same in different phonological contexts of Persian and Kurdish.

One of the most common complaints expressed by individuals with hearing-impairment is the difficulty in speech perception in background noise. Different tests have been developed for the evaluation of reduced ability of speech perception in noise, and the Consonant-Vowel in noise test is one of the simplest one regard to speech materials. The goal of the present study was development and determined validity and reliability of the Persian version of the Consonant-Vowel in noise test, among 18 to 25 year old Persian speaking because of the lack of a Persian version of this test.
This was a tool-making research that had 3 main stages: development of the Persian version of the Consonant-Vowel in noise test (4 lists and each list in 5 different signal to noise ratio), examination of its content validity, and its administration on a total of 50, 18 to 25 year normal hearing individuals (20 men /30 women) that selected by random sampling method, in order to examine the reliability of the test from the students of the University of Social Welfare and Rehabilitation Sciences, Tehran, Iran. For descriptive reports, central tendencies and indices of dispersion were used and for statistics relations; Pearson correlation test, intra-class correlation coefficient (ICC), paired t-test and independent t-test were used.
The content validity ratio for each item was acceptable (CVR>0.62). The lists number 2, 3, and 4; and also the lists number 1 and 4 in the Consonant-Vowel in noise test, were highly correlated (P0.05) and also men’s and women’s scores (P>0.05). Participant's performance improved as the SNR increased.
According to the study results, it can be concluded that the Persian version of the Consonant-Vowel in noise test has acceptable content validity and reliability, and can be used in clinical and research works.

This study aimed to investigate first three formants of Persian language among 18-24 years old university students. In a descriptive and cross-sectional study, 60 students (30 males and 30 females) aged 18-24 years were selected from school of Persian language and Isfahan University of Medical Sciences. The data were gathered directly by the interviewer; and the Persian vowel producing test was performed on the samples. Then first, second, and third formants of every six vowels were obtained by the Real analysis program of Dr. Speech software and Speech Studio, and their scores were recorded in the table, and investigated finally based on the goals and questions of the study. The greatest mean amount of F1, F2, and F3 were for vowel /æ/ 767 Hz, vowel /i/ 2244 Hz, and vowel /i/ 3129 Hz, respectively; and the least amount was for vowel /i/ 255 Hz, /u/ 734 Hz, and /u/ 2317 Hz, respectively, among the male students.The greatest mean amount of F1, F2, and F3 was for vowel /æ/ 876 Hz, vowel /i/ 2688 Hz, and vowel /i/ 3339 Hz, respectively; the least amount was for vowel /u/ 376 Hz, /u/ 731 Hz, and /u/ 2412 Hz, respectively, among the female students. The vowels /i/ and /u/ are close and the vowels /æ/ and /a/ are open and two vowels /o/ and /e/ are located between these two groups. The vowels /i/, /e/, and /æ/ are anterior and vowels /a/, /o/, and /u/ are posterior. The vowels /i/, /æ/ are expanded and the vowel /e/ is semi-expanded. The vowels /a/ and /u/ are circular and the vowel /o/ is semi-circular.

This paper studies the phonetic aspects of vowel reduction in Persian. Vowel reduction was examined in unstressed syllables using duration and F1 and F2 spectral values across different consonantal contexts. Results showed a strong effect of stress on duration across all consonantal contexts, but the results for F1 and F2 frequencies varied with vowel type as well as consonantal context. Most vowels had non-significant formant changes in unstressed condition as compared to stressed condition; however, the vowel /a/ had significant spatial reduction in the direction of the center of the vowel space. The results support neither of the two known articulatory hypotheses concerning vowel reduction, namely, centralization (in unstressed position) by target undershoot, and reduction due to co-articulation with the consonant context. Instead, the results lend support to the dispersion theory of speech perception which argues that vowel systems cross languages tend to utilize the available acoustic vowel space so that maximal auditory contrast is maintained. It is further argued that the position of vowels in the acoustic vowel space is influenced by this dynamical repelling force which has come to be called adaptive dispersion.

Persian has two low vowels, namely, the front vowel /a/ and the back vowel /ɒ/, while Japanese has only one low vowel which is phonologically a back vowel, but phonetically a central one. In the present study, the research question is whether Japanese learners of Persian language are able to produce the Persian front and back low vowels distinctively or not. In order to answer this question, Japanese learners of Persian language were asked to produce Persian and Japanese low vowels in the target words. Native speakers of Persian also produced the same Persian words. Then, the frequency of the first and the second formants (F1 and F2) of low vowels were measured.Thefrequency of the first and the second formants of Persian low vowels in the Japanese learners’ production were compared to that of the Persian native speakers. The statistical analyses revealed that Japanese learners produce the two Persian low vowels without a significant difference and almost similar to the Japanese low vowel. Extended abstractPersian has two low vowels, namely, the front vowel /a/ and the back vowel /ɒ/, while Japanese has only one low vowel which according to (Labrune, 2012) and (Kubozono, 2015) is phonologically a back vowel, but phonetically a central one. When Japanese native speakers learn Persian as a foreign language, they tend to map the high and the mid vowels of their language onto the high and the mid vowels of the target language due to the similarity between the number and the quality of these vowels. However, producing Persian low vowels is potentially problematic for Japanese native speakers since Japanese has only one low vowel while there are two low vowels in Persian. In the present study, the main research question was whether Japanese learners of Persian language are able to produce the Persian front and back low vowels distinctively or not. This study also tried to reveal the acoustic characteristics of the Persian low vowels produced by learners with Japanese L1. The findings of this research can be used in teaching Persian as a foreign language to native speakers of Japanese and specially in designing specific pronunciation drills for them. In order to answer the above questions, a production test was designed and conducted in which learners of Persian language with Japanese L1 produced Persian and Japanese words containing low vowels. Native speakers of Persian also produced the same Persian words. The vowels of both languages were presented in an unstressed position in disyllabic or trisyllabic words. In this experiment 12 participants (six Japanese speakers and six Persian speakers) took part. Persian speakers were learners of Japanese language in Iran, and had studied the language for two years in the university. Their age ranged from 20 to 22, with the average of 20.6 years. They were all classmates, and none of them had ever been to Japan. Japanese speakers had been studying Persian for at least two, and at most three years in Japanese universities. Their age ranged from 21 to 30 with the average of 24.5 years. They all had a 1-3 month stay in Iran. The utterances were recorded at a sampling frequency of 44,100 Hz in a phonetic laboratory and were analyzed using the phonetics software Praat (Boersma&Weenink, David, 2019).  Next, the frequency of the first and the second formants (F1 and F2) of Persian low vowels produced by Japanese learners was measured based on the method explained in (Bijankhan, 2013, pp. 149-150) and was compared to the F1 and F2 of Persian low vowels produced by native speakers. The results of the measurements which are presented in the form of tables and graphs in the paper, suggest that although Persian native speakers produce the front and the back low vowels distinctly, Japanese learners of Persian produce the two Persian low vowels with a similar quality, i.e., with similar F2 amounts. In statistical analyses, first a Cronbach's alpha test was used to determine the internal consistency of the data. Then, a paired dependent samples t-test was used to determine if there were significant mean differences in F1 and F2 in subject groups. The inferential statistical analyses of the test results revealed that there is no significant difference between the F1 of Japanese and Persian low vowels produced by native speakers and language learners which was not surprising because all the vowels in question were low vowel. However, on the other hand, native speakers of Persian produced Persian low vowels with significantly different F2, while there was no significant difference between the F2 of Persian low front vowel and low back vowel produced by Japanese learners. In other words, when Japanese learners produce Persian low vowels, there is an overlap between the spaces of these two vowels. Comparisons between the F2 of Persian vowels produced by Japanese learners with the F2 of the Japanese low vowel showed that in fact, Japanese learners tend to produce both Persian low vowels similar to the low vowel in Japanese. In order to train the language learners in Japan to produce Persian low vowels distinctly, both traditional methods such as drills utilizing minimal pairs and new computer-assisted comparative methods such as sound visualization can be used.