The three parts of speech

Every Arabic word is one of three kinds:

• Ism (noun): a person, place, thing or idea. It can take al- or tanween: كِتَابٌ، الْمَسْجِد.
• Fi'l (verb): an action tied to a time: كَتَبَ (he wrote), يَكْتُبُ (he writes).
• Harf (particle): it only has meaning with other words: فِي (in), مِنْ (from), هَلْ (a question word).