Devoir is a very common French verb with irregular conjugations and an unusual relationship to some of its English equivalents. It has several meanings related to obligation, supposition, and expectation.
Devoir and falloir are fairly synonymous, but these two French verbs are not interchangeable. Their meanings are slightly different, and they each have additional meanings, depending on how they're used.
Dire is one of the most common and useful French verbs and has irregular conjugations. It literally means "to say" or "to tell," and is also found in many idiomatic expressions.
The third person plural verb ending -ent is often not pronounced. The rules for when and how to pronounce it are fairly straightforward: it has to do with two completely different issues.
Two dozen French verbs always require a reflexive pronoun but aren't necessarily reflexive or reciprocal. It's essential for these verbs to be used pronominally, as without the pronoun, the verb is meaningless.
Être is one of the two most important French verbs. It literally means "to be," but also serves as an auxiliary verb and is the key to the passive voice.
Faillir has no direct verbal English equivalent when used as a semi-auxiliary verb; English needs an adverb or a short phrase to capture the meaning, such as "to almost do."
The causative is a grammatical construction with a lazy subject who, rather than performing some action himself, is making someone or something else do it: to make something happen, to have something done.
One of the most common and useful French verbs, faire literally means "to do" or "to make" but it's also found in many idiomatic expressions and is the key to the causative construction.