Learn Arabic (Modern Standard): يأكل أخي بسرعة.

In Modern Standard Arabic, sentences usually start with the verb. This is called a verbal sentence. So, instead of saying 'My brother eats quickly' (Subject-Verb), you say 'Eats my brother quickly' (يأكل أخي بسرعة). You can say أخي يأكل بسرعة, but starting with the verb is the most standard, natural way to structure it in formal Arabic.

How does the word بسرعة translate to 'quickly'?

Arabic doesn't have a direct equivalent to the English '-ly' ending to make adverbs. Instead, you often use the prefix بـ (which means 'with' or 'by') attached to a noun. Here, سرعة means 'speed,' so بسرعة literally means 'with speed,' which gives us 'quickly.'

I see the word for 'brother' (أخ) in أخي, but where is the word for 'my'?

In Arabic, possessives like 'my,' 'your,' or 'his' are not separate words; they are attached to the end of the noun as suffixes. The suffix for 'my' is the letter ـي (yaa). When you add it to أخ (brother), it becomes أخي (my brother).

How do we know يأكل means he eats, rather than someone else?

In the present tense, the first letter of the verb tells you who is doing the action. The prefix يـ (ya-) at the beginning of يأكل is used for 'he' (third-person masculine singular). If it were 'she eats' or 'you (masculine) eat', it would start with a 'taa' instead: تأكل (ta'kulu).