Lenition of /b/ in Digehsaraee Taleshi Dialect within the Framework of Optimality Theory

Introduction
The scientific study of local languages ​​and dialects can provide many theoretical and scientific results and help in better understanding of language knowledge and its enrichment. Taleshi as one of the coastal languages ​​of Caspian Sea belongs to the languages ​​of the north western group of Iranian languages. This dialect is related to other dialects of the Caspian coast and also connected with the central dialects of Iran. Some linguists have divided Taleshi into three groups: Northern Talshi common in the Republic of Azarbaijan, Central Taleshi common in more southern regions such as Asalem and Paresar as a section of Razvanshahr, and Southern Taleshi common in Shanderman, Masal, Shaft, Foman and Somaesara, which is closer to Tati and there is mutual understanding between them. (Stillo, 2015: 413).
The present study explains the lenition of the consonant /b/ in the Taleshi dialect of Digehsaree within the framework of optimality theory. This process happens at the end of the syllable, in consonant clusters, and between vowels. Sometimes, it occurs at the beginning of the syllable which have been discussed for its historical reasons.
The current research, which was conducted in a descriptive-analytical method and based on the theory of optimality, seeks to find answers to such questions as: What is the mechanism of the lenition in Taleshi Digehsaraee dialect regarding the consonant /b/ in different environments? In which environment lenition does not occur? What are the active restrictions concerning this process and what are their order?
Research background
The studies conducted on phonological processes in different dialects and languages within the theoretical framework of optimality are discussed. The methods in aforementioned studies are descriptive-analytical, and the results indicate that there are various processes of assimilation, dissimilation, insertion, deletion, compensatory lengthening, lenition and strengthening in these dialects and languages. The analysis of data on the constraints and the different arrangements of constraints in each language and dialect has been very useful and effective in conducting this research. The present research rejects Hart's theory that the lenition does not occur in the initial or inter-vowel position. In Taleshi Digesaree dialect, lenition also happens in the position between two vowels.
Research Methods
The approach of this study is the phonological system of the Taleshi-Digehsaree dialect, a formal approach, aimed at the normal speech of native speakers. The method used in the phonetics and phone extraction section is generally based on examples of the normal speech by the speakers of this dialect. To conduct this research, twenty illiterate native speakers of Digehsara village with an age range of 40 to 70 (ten women and ten men) were interviewed for one hour and the data were recorded. Also, the author is a speaker of this dialect and the research method is descriptive-analytical. The theoretical framework in this research is the theory of optimality, which is one of the dominant theories in the present decade and is considered very popular and influential in linguistics. The main goal of this theory is to compare options according to a hierarchy of constraints.
Results and discussion
The factor that provokes lenition in Taleshi Dialect of Digehsaraee should be the restriction of not having a consonant with the characteristic *[-cont – delrel+voice+labial] after the center of the syllable. There are cases that with the lenition of the first consonant in syllable-final consonant clusters but there is still a sequencing problem. For example, the word Qabz is pronounced as Qafz, which still has a sequencing problem. There is another evidence that the lenition in syllable-terminal clusters is not a restriction of sonority sequence. Definitely, in the clusters at the end of the syllable of the word / zabt /, the sequence of articulation is well observed and we see a descending sequence of articulation at the end of the syllable. Applying lenition to observe the sonority sequence will be a mistake and this is against the principle of linguistic economy. Therefore, the lenition must have another stimulus. So, it can be concluded that in Taleshi Dialect, the sound after the core should not have the characteristic *[-cont – delrel+voice+labial]. According to the above limitation, the tendency of the language is that the obstruent sound /b/, which has the characteristic of [-continuous-delayed release + vowel + labial], should not come after the nucleus and if it occurs, this violation should be compensated as much as possible. Therefore, Taleshi Dialect uses lenition. The transformation of obstruent into fricative consonants, called friction, occurs in the context between two vowels or after a vowel, so that it is considered a kind of lenition. (Kenstowicz, 1994) This is somewhat equivalent to constraint * [-cont - delrel+voice+labial] due to the absence of the obstruent consonant /b/, and it has the characteristic of *[-cont – delrel+voice+labial] after the nucleus.
In Taleshi Dialect of Digehsaraee, the constraint *[-cont-delrel+voice+labial] is applied to non-cluster consonants in addition to consonant clusters at the end of the syllable. For example, the inflectional form of the word water /ᾱb/ is pronounced as /ᾱv/. This constraint is also applied in the position between two vowels. For instance, the word bean /Lubјᾱ/ is pronounced as /Luvјᾱ/. The word /dubᾱre/ is pronounced again as /dǝvᾱra/. It can be seen that the consonant /b/ between the two vowels has also been transformed into the fricative consonant /v/ using the lenition to satisfy the *[-cont – delrel+voice+labial] constraint. Therefore, this can be considered as a dominant constraint in Taleshi dialect. This constraint is also applied in the v-c# position, i.e. between a vowel and a consonant at the end of the syllable. For example, the word tiger /babr/ is pronounced as/ bavr/ or the word patience /sabr/ as /savr/. This constraint is also applied in the v:-# position, i.e. after the long vowel at the end of the syllable. The word šib is pronounced as šiv or the word sib is pronounced as sif. The consonant /b/ after long vowels also satisfies the constraint *[-cont– delrel+voice+labial].
Some of the words in the Taleshi dialect, such as [var] barf, [vᾱ] wind, [vang] bang, have historical roots before being affected by the lenition. In other words, the original (old) form of these words in the languages Avestan and Middle Farsi are in their modern form and are still preserved in some dialects, including the Taleshi dialect. But in a certain context, the /b/ consonant is not affected by the *[-cont – delrel+voice+labial] constraint and remains the same as the /b/ consonant. This happens if we have a syllable (rv:) before the phoneme /b/, the lenition is not applied in this environment. The stimulus of this factor should be seen as the constraint * [+liquids-lateral+ long v+ cons(v)]. So, the sequence of constraints governing the Taleshi Digehsaraee dialect can be written as follows.
*[+liquids-lateral+ long v+cons(v)], LIN, MAX, DEP,>> SON-SEQ, *[-cont– delrel+voice+labial], IDENT(f), >>Complex Coda
Conclusion
The stimulus of the lenition should be considered as the constraint *[-cont – delrel+voice+labial]. The tendency of this constraint is that the phone after the nucleus does not have the characteristic * [-cont – delrel+voice+labial]. According to this constraint, there is a tendency in Taleshi Digehsaraee dialect in which the obstruent consonant /b/ does not come after the nucleus, and if it does, this violation is compensated as much as possible. The constraint *[-cont – delrel+voice+labial] applies to non-cluster consonants in addition to consonant clusters. But in a certain context, the consonant /b/ is not affected by the constraint *[-cont – delrel+voice+labial] and remains the same consonant /b/. This happens if we have a syllable (rv:) before the consonant /b/, which the lenition is not applied in this context. The stimulus of this factor should be known as the constraint* [+liquids-lateral+ long v+ cons(v)], which means that whenever we have a long vowel after /r/, the lenition is not applied. The reason for this is related to the phonological system of the Taleshi dialect, which does not allow such a sequence within a syllable in the Taleshi dialect.