Learn Arabic (Modern Standard): في أي سن تعلمت القراءة؟

When asking "how old are you?" you use كم عمرك (literally "how much is your age?"). However, when asking "at what age" a specific event happened, Arabic uses في أي (literally "in which"). It pairs with سن or عمر to mean "at what age".

Why is the word for "age" (سن) right after أي written without an article?

The word أي (which/what) acts like the first word in a possessive phrase (an Idafa). The noun immediately following it must be indefinite and in the genitive case. So it is always أي سن (what age) and never أي السن.

I thought سن meant "tooth". Can I use عمر here instead?

Yes! سن can mean both "tooth" and "age" depending on the context. You could perfectly well say في أي عمر here, and it would mean exactly the same thing.

The English translation says "learn to read". Why does the Arabic use the noun القراءة (the reading) instead of a verb?

In Arabic, verbs expressing learning, liking, or starting often take a verbal noun (Masdar) as their direct object. So instead of saying "learned to read" with a verb, Arabic uses the definite noun and says "learned the reading" (تعلمت القراءة).

How do I know if تعلمت is addressed to a male or a female?