Learn Arabic (Modern Standard): أين القط؟

In Arabic, there is no word for "is" or "are" in the present tense. To say "Where is the cat?", you simply put the question word أين (where) right before the noun القط (the cat). This creates a complete sentence without needing a verb!

How do we know this means "the cat" and not just "a cat"?

The prefix الـ attached to the beginning of the word makes it definite, meaning "the". If you remove it, you get قط (a cat). In Arabic, "the" is never a separate word, but always a prefix attached directly to the front of the noun.

Should I pronounce the "L" sound in القط?

Yes, you pronounce it clearly as "al-qiṭṭ". The letter that comes right after the prefix, ق, is a "moon letter". That means it plays nicely with the ل (L) and lets you pronounce it fully. If it were a "sun letter", the "L" sound would disappear and you would double the following letter instead.

Could I change the word order and say القط أين؟?

No, you should stick to أين القط؟. In Arabic, question words like أين (where) naturally jump to the very beginning of the sentence, even when you are asking about a specific, definite subject like "the cat".