Here are some additional things to keep in mind about the primary Persian determiner, the indefinite enclitic:
Remember that یی ,ای , and ئی are orthographic variations of the same feature; hence خانه ییxānei ‘a house’ خانه ای, and خانه ئی are the same, although through time some forms have become more common: خانه‌ای , گیسویی , دریایی , صندلی‌ای .
It must be understood that the ئی form (with hamze) is not really correct; as explained in the section dealing with hamze, this feature belongs exclusively to the Arabic words and cannot be taken as a Persian grammatical feature. Therefore it is preferable to use یی and ای, rather than ئی.
On the other hand, in the case of the Arabic loanwords, the usage of hamze is necessary and /alef/ or /یـ/ may not be used in these words. It is only in words and features of Persian origin (suffixes, enclitics, etc.), that the usage of the hamze is inadmissible: رئیس (Arabic ‘chief, master’), but آیینه (Persian ‘mirror’), never write آئینه.
Although the indefinite enclitic ی is mobile and can be placed at the end of the noun or the adjective by choice, it is more common that in the nouns or adjectives with a final ی, the indefinite enclitic attached to the word which does not end in a final ی: صندلی بزرگی sandali-ye bozorgi ‘a big chair’, instead of صندلی‌یی بزرگ , which is not incorrect, but is hard on the tongue. Therefore, to say پیراهنی یشمی pirāhani yašmi ‘(an) olive-green shirt’ is more comfortable to pronounce than پیراهن یشمی‌یی , etc.
In a segment in which a noun is modified by more than one adjective, the indefinite enclitic is either attached to the noun or the last adjective. The order of the adjectives is not as specific as in English:
خانه‌یی بزرگ، سفید و زیبا
xānei bozorg sefid va zibā
‘a big, white and beautiful house’
or
خانهٔ بزرگ، سفید و زیبایی
xāne-ye bozorg sefid va zibāi
‘a big, beautiful, white house’
In the Colloquial Persian the indefinite enclitic always comes after the noun-adjective segment. That is to say, instead of خانه‌ای زیبا xānei zibāi ‘a beautiful house’, مردی بزرگ mardi bozorg ‘a big/great man’ , کتابی مفید , ketābi mofid ‘a useful book’, etc. خانهٔ زیبایی xāne-ye zibāi ‘a beautiful house’ , مرد بزرگی mard-e bozorgi ‘a big/great man’, کتاب مفیدی ketāb-e mofidi ‘a useful book’, etc. are used colloquially.
As a result, since in such noun-adjective segments as پیرهن یشمی the indefinite ی is expected to come after the ی of the adjective یشمی, in the spoken Persian it is more common to use the word ye (formal yek ‘a, one’) instead of the indefinite enclitic: ye piran-e yašmi, ye sandali-ye bozorg, etc.
It is normal in Colloquial Persian to combine ye ‘a’, and the indefinite enclitic (which means ‘a’ as well):
Instructional Technology Services