In spoken Persian the numbers also undergo some modifications as well:

Although technically yek ‘a, one’ and the indefinite ی ‘a’ cannot be used together with the same noun, in spoken Persian they are always used together in dependant clauses; for example, یه مردی بود ye mard-i bud… ‘there was a man…’ (very sporadically ye mard bud; but never mard-i bud), یه کتابی خریدم ye ketāb-i xaridam… ‘I bought a book…’, etc. In poetry occasionally this occurs because of the timing of the verse. For instance, in the following distich, Mowlānā Jalāl ud-Din Balkhi (aka Rumi), instead of یک شبان yek šabān has used یک شبانی yek šabān-i; because شبان šabān is disyllabic while he needed a trisyllabic word:
did musā yek šabāni rā be rāh دید موسی یک شبانی را به راه

‘once Moses saw a shepherd on the/his way’

Although Persian does not have a definite article of any sort, and a noun is only syntactically introduced as definite, the spoken Persian has an [-e] enclitic, which functions as a definite article. This [-e] takes the stress:

(Note: In the Persic dialects, such as Shirazi, Bushehri, etc., this definite enclitic is [-u], which just like its Standard Persian counterpart, takes the stress; as in مردو mardu^|, زنو zanu^|, کتابو ketābu^|, ‘the man,’ ‘the woman,’ ‘the book,’ etc.)