Conjugation in spoken Persian

In spoken Persian, the conjugational endings are:

past present comment
1S -am -am
2S -i -i
3S - -e «-ad» changes to «-e»
1P -im -im
2P -in -in the same «-id» is also heard
3P -an' -an' the final «d» of «-and» drops but
the same «-and» is also heard

Look at the conjugation of «neveshtan» (to write):

past simple present imperfect present subjunctive
1S neveshtam نوشتم minevisam مینویسم benevisam بنویسم
2S neveshti نوشتی minevisi مینویسی benevisi بنویسی
3S nevesht نوشت minevise مینویسه benevise بنویسه
1P neveshtim نوشتیم minevisim مینویسیم benevisim بنویسیم
2P neveshtin نوشتین minevisin مینویسین benevisin بنویسین
3P neveshtan' نوشتن minevisan' مینویسن benevisan' بنویسن

Narrative tenses

In narrative tenses, the past participle and the past endings go on a contraction. For example: «neveshte+am» becomes «nevesht'am». Please note that «neveshtam» (I wrote) and «nevesht'am» (I have written» are not pronounced identically. In «neveshtam» the stress falls on the syllable right before that of the ending (the penultimate): «ne.vesh.tam», whereas in «nevesht'am» the stress is on the last syllable: «ne.vesh.tam». The only form that remains distinct in writing is 3S as it doesn't take ending. See:

past simple past narrative
1S neveshtam نوشتم nevesht'am نوشتم
2S neveshti نوشتی nevesht'i نوشتی
3S nevesht نوشت neveshte نوشته
1P neveshtim نوشتیم nevesht'im نوشتیم
2P neveshtin نوشتین nevesht'in نوشتین
3P neveshtan' نوشتن nevesht'an' نوشتن

As you see, Perso-Arabic (PA) script doesn't have a character to denote contractions. Unfortunately, this causes past simple and past narrative appear alike in writing (but not in speech, as explained). Even native speakers occasionally make a mistake in telling them apart. For example, when writing down a recorded informal interview…

Zabt e kâr yâ âlbom e tâze i ro shoruø kardi? ضبط کار یا آلبوم تازه‌ای رو شروع کردی؟

…where «shoruø kardi» شروع کردی is in past narrative and must be written:

When writing in informal Persian in Perso-Arabic script, there's no way to write past narrative correctly (in fact, contractions in general). But when writing in Latin script, contractions can be shown with apostrophe: shoruø kard'i

TIP Although the difference can easily be detected from speech, noting the stress position but it can also be detected from the 3S form, which remains distinct. In order to decide whether شروع کردی is a narrative, you can simply consider the sentence in 3S form. For example, here it would be شروع کرده, which means the tense is past narrative. This tip can also be used for other narrative tenses. Example:

Considering it in 3S form, shows that it would شنیده بوده and thus, this tense is past precedent narrative and not past precedent! Writing it in written language:

Further reductions

Historically, there's a common phonemic change in the evolution of Persian: reduction of VCV to V (V = vowel; C = consonant). That is to say, whenever a word has a VCV pattern, it is disposed to be reduced to either V's some time in the evolution of the language:

VCV pattern and its reduction are in bold
Old Persian Middle Persian New Persian
shiyâti shâti —> shâdi shâdi
chavant chant —> chand chand
duvar dar dar

New Persian is more than 1100 years old. So, it is fairly natural to witness similar changes happened through this long period. Our written language is very preservative but the spoken language has evolved freely. Interestingly, the VCV pattern has also occurred in New Persian. Examples from verb category (more examples in the article VCV Pattern):

raftan /rav/ goftan /gu/
1S miravam miram miguyam migam
2S miravi miri miguyi migi
3S miravad mirad —> mire miguyad migad —> mige
1P miravim mirim miguyim migim
2P miravid mirid —> mirin miguyid migid —> migin
3P miravand mirand —> miran' miguyand migand —> migan'