Kurdish belongs to the Western Iranian branch of Indo-Iranian branch of the Indo-European family. The most influential varieties of Kurdish dialects are Sorani سۆرانی and Kurmanji kurmancî respectively. Although it is more familiar to state them Kurdish كوردی/kurdî. The line dividing Sorani and Kurmanji permeate roughly diagonally from the northeast and southwest Kurdistan. By the means of dividing was linguistic related.
Kurmanji, the dialect of the vast majority of speakers populated in northern Kurdistan that covers Turkey, Syria, Armenia and Azerbaijan, and of a few in the extreme northwest Iran and the northern most tip of Iraq. And Sorani is another dialect that is predominantly spoken in southern and eastern Kurdistan, Iraq and Iran. Although those two dialects are closely related even though they are not mutually intelligible and differ at the basic structural level as well in vocabulary and idiom. Since all varieties of Kurdish dialects are not only closely to Persian, but have also been massively influenced by Persian, especially Farsi, the dominant literary and cultural concept of the area for the last millennium. Kurdish is best approached with knowledge of Persian, and for that reference to Persian syntax has been freely made throughout the presentation of the grammar.
Sorani has been the second official language of Iraq since the establishment of a semi-autonomous Kurdish state after World War I and has many decades of literary activity behind it. This dialect is written in an adapted Perso-Arabic script which originates from reforms under the Ottoman Empire which intended to improve Ottoman Turkish spelling and which is why Sorani Kurdish shows vowels more than Persian or Arabic.
Kurmanji continuously encounters many deplorable approach from Turkish and Syrian political policies which has been caused many difficulties to get it a unified, normalized or standardized language. However, progressive linguists among émigré communities in Europe recently begun its publication in Kurmanji. But the problems of Kurmanji persist due to the abundance of regional dialects, which is not possible to provide a lucid description of all the variants. Kurmanji has been Sovietized which some of them still writing it in Cyrillic script in the Kurdish-speaking regions of Armenia and Azerbaijan. After the Soviet regime, it has been either converted back to Latin script and lack of evidence that it has also written in Armenian script. Current script is mostly written in Latin script. An example of the two scripts:
K: Kurdistan welatekî Rojhilata Navîn e û welatê Kurdan e.
S: کوردستان ناوچەیەکی لە رۆژهەڵاتی ناوینه و ناوچەیەکەی کوردانە. (Kurdistān nāwçeyekî le rojhełatî nāwîná û nāwçeyekeyi kurdāná.)
Kurdistan is a country in the Middle East and is the country of the Kurds.
In terms of phonology, there are not many differences, although the above example you can see the words ‘navîn’ or ‘ناوین’ which both mean ‘middle’, but the ‘v/و’ are pronounced /v/ and /w/ respectively. There are a few other sounds in Sorani which do not exist in Kurmanji, such as the dark l/ɫ/. There are other differences, but I will not go into them since phonology is not very accessible for me as I am deaf. I want to minimize mistakes as much as possible.
Beyond superficial differences, the main divergence can be found in the fact that Kurmanji has both cases and gender whereas does not. Like other Iranian languages, such as Zazaki, Pashto and Balochi, Kurmanji has nominative and oblique case as well as vocative case. It has a masculine and feminine gender and one plural. Sorani, most likely under the influence of languages, such as Persian which also has no gender or case anymore, has lost these aspects.
In Kurmanji there is a difference between ‘I’ and ‘me’ (‘ez‘ and ‘min‘ respectively) and this goes for all nouns. In Sorani, there is only one form, so ‘I/me’ is ‘min‘ – thus a sentence like ‘I know’ would, for a Kurmanji speaker, sound like ‘me know’ in Sorani. The object in Sorani often becomes an enclitic infix in the verb. Take the phrase ‘I see you‘ for instance:
K: Ez tê dibînim
Here ‘tê‘ is the oblique form of ‘tu‘ – you.
S: من) دەتبینم) / (min) datbînim.
Here, the object infix ‘-t-‘ from ‘tu’ is placed after the verbal prefix and before the root of the verb.
Another instance: you see me
K: Tu min dibînî.
S: تو) دەمبینی) / (tu) dambînî.
Both languages have split ergativity which means that in the past tenses the logical subject becomes the grammatical object and vice versa, although only with transitive verbs. This is fine for Kurmanji with its cases because it can easily say something like ‘him I saw’ to mean ‘he saw me or ‘me he saw to mean ‘I saw him’. However, since Sorani has no cases, this becomes more complex and instead the subject becomes object infix or suffix attached where it can be, that includes sometimes the end of the verb, giving it the appearance of being non-ergative. Some examples:
I eat the bread > I ate the bread
K: Ez nan(î) dixwim > min nan xward
Here ‘dixwim‘ in the present agrees with the subject whereas ‘xward‘ in the past agrees with the object. ‘Nan(î)‘ is the oblique of ‘nan‘ – bread, but in most dialects, it does not carry the masculine oblique marker ‘î‘.
S: من) نان دەخۆم > نانم خوارد) / (min) nān dakhom > nānim khwārd
As can be seen, the logical subject becomes an object infix/suffix and, in this case is stuck onto the logical object. If the phrase were simply ‘I eat’, this would be attached the end of the verb making: khwārdim.
The ezāfe construction, is a grammatical particle found in some Indo-Iranian languages, which is used to connect nouns to other nouns (like ‘of’ and ‘s’ in English) and adjectives to nouns, also differs between the two, largely due to the existence or not, of gender. In Kurmanji the ezāfe is simply added to the end of any noun but depends on the gender and number of the noun. Thus, the word ‘jin‘ (f.) – woman, ‘mirov‘ (m.) – man, and ‘zarrokan‘ (pl.) – children are inflectable when attached to another word such as in the following instances:
jina mezin – the big woman
mirovê mezin – the big man
zarrokên mezin – the big children
In Sorani, there are no genders, but there are two ezāfe forms. The simple one is the same for all nouns and is made by adding ‘-i’ to the end of the noun, as in:
ئەفرەتی بچووک / afrati biçûk – small woman
منداڵانی بچووک / mindāɫi biçûk – small children
However, there is another slightly different form which is used in when the linked phrase is modified by the demonstrative (this, that) or the definite article (but not the indefinite). The definite article, which does not exist in Kurmanji, is formed by adding ‘-aká’ to the end of the noun, or the end of the end of the attached adjective and as can be seen this carries the stress. The demonstrative adds a stressed ‘-á’ to the end of the noun/adjective. Thus we get:
هۆتێلەکە / hotelaká – the hotel
هۆتێلە باشەکە / hotela bāshaká – the good hotel
ئەم هۆتێلە / am hotelá – this hotel
ئەم هۆتێله باشە / am hotela bāshaká – this good hotel
With an indefinite noun, the normal ‘-i’ ezafe is used:
هۆتێلێکی باش / hotelèki bāsh – a good hotel
Finally, there is a difference in how the two languages form the passive tense. In Kurmanji the verb ‘hatin’ -to come is used with the infinitive of the verb. Examples:
Mirovan hatin kuştin. – the men were killed (lit. the men came to-kill).
In Sorani, the passive is formed by adding ‘-rā’ to the present stem of transitive verbs to make a new passive infinitive. From this you can make past and present passives as well as passive participles. In the present the ‘-rā’ becomes ‘-re’, as in:
bîn – present stem of ‘to see’ -> bînran – to be seen, bînra – it was seen -> dábînre – it is seen/can be seen.
پیاوەکان کوژران / pyawakán kuzhrān – the men were killed (‘kuzh-‘ is the present stem of ‘kushtin’ -to kill).
As can be seen from the differences that I have outlined above, there are enough grammatical differences to warrant Kurmanji and Sorani being considered distinct language groups rather than continuum. Naturally, Kurmanji speakers and Sorani speakers, as well as most Zaza and other Kurdish language speakers consider themselves ethnic Kurds and if that is how they see themselves, then that is what they are – after all language and ethnicity are not the same thing.