Learn Arabic (Modern Standard): أين الجار؟

Yes! In Arabic, question words like أين (where), من (who), and ما (what) almost always come at the very beginning of the sentence, just like they do in English.

Where is the Arabic word for "is" in this sentence?

There isn't one! In Arabic, you don't use words like "am", "is", or "are" in present-tense sentences. You simply put the parts of the sentence next to each other. So, أين الجار؟ literally translates to "Where the neighbor?".

Does الجار refer to a male or a female neighbor?

It refers to a male neighbor. If you were asking about a specific female neighbor, you would add the feminine ending (taa marbuutah) to the end of the noun, making the question أين الجارة؟.

Why is ال attached directly to the word جار?

In Arabic, the definite article ال (meaning "the") acts as a prefix. It is always attached directly to the beginning of the noun, rather than being written as a separate word.