Learn Farsi: بچه سعی می‌کند نیفتد.

To make a verb negative in the subjunctive, we replace the positive prefix بـ (be-) with the negative prefix نـ (na-). The verb here is افتادن (to fall), whose present stem is افت (oft). So instead of the positive بیفتد (biyoftad), we get نیفتد (nayoftad).

Why is there a ی (y) in the middle of نیفتد (nayoftad)?

When we add the prefix نـ (na-) to a verb stem that starts with a vowel like افت (oft), we insert a 'y' sound to make it easier to pronounce. This stops the vowels from crashing together, giving us nayoftad instead of 'na-oftad'.

Why do we use the subjunctive form for 'fall' in this sentence?

In Farsi, when you use a verb that shows intention or an attempt, like سعی می‌کند (tries), the second verb must be in the subjunctive mood. It shows the action is a goal or possibility, rather than a stated fact.

Where is the word 'to' in this sentence?

English uses 'tries not to fall' (verb plus infinitive), but Farsi connects two conjugated verbs. Literally, the sentence is 'The child tries that he not fall'. Both سعی می‌کند and نیفتد are conjugated for the third person singular, and the connecting word for 'that' (که) is often dropped in everyday Farsi.