O desviador move a corrente.

Because Portuguese normally uses definite articles very often with nouns.

• o desviador = the derailleur
• a corrente = the chain

The article has to match the noun’s gender and number:

• o = masculine singular
• a = feminine singular

So here desviador is treated as masculine, and corrente as feminine.

This is grammatical gender. In Portuguese, every noun is assigned a gender, and the article and some other words must agree with it.

• desviador is masculine, so it takes o
• corrente is feminine, so it takes a

This does not mean the objects are biologically male or female. It is just part of how the language works.

A useful pattern is that many nouns ending in -dor are masculine, such as:

• o motor
• o computador
• o desviador

But you should still learn each noun with its article.

move is the 3rd person singular present indicative of the verb mover.

So:

• mover = to move
• eu movo = I move
• tu moves = you move
• ele/ela move = he/she/it moves

In this sentence, the subject is o desviador, which is singular, so the verb is move.

Because mover is the infinitive, meaning to move. In a normal statement, Portuguese usually uses a conjugated verb.

So:

• mover = to move
• move = moves

That is exactly the same kind of difference as English to move vs moves.

Yes. This sentence follows the common subject + verb + object pattern:

• O desviador = subject
• move = verb
• a corrente = direct object

So the structure is very similar to The derailleur moves the chain.

Yes, in this context desviador refers to the bicycle derailleur.

More literally, desviador comes from desviar, which means to divert, to shift, or to move aside. So desviador is something that redirects or shifts something.

In bicycle language in Portugal, desviador is the normal term for the mechanism that shifts the chain.

Yes. Corrente can have several meanings, including:

• chain
• current, especially electric current
• stream/flow, in some contexts

Here, because of desviador, the meaning is clearly chain.

So context is what tells you which meaning is intended.

Usually mover is the better choice here.

• mover = to move something
• mexer often means to move, to stir, to fiddle with, or to tamper with, depending on context

For a mechanical action like a derailleur moving a chain, mover sounds more direct and natural.

So O desviador move a corrente is a straightforward, natural sentence.

A rough pronunciation guide is:

u dsh-vya-DOR MOV(uh) a koo-REN-tuh

A few important points for European Portuguese:

• desviador is stressed on the last syllable: -dor
• move is stressed on mo-
• corrente is stressed on -ren-
• unstressed vowels are often reduced in European Portuguese, so some vowels sound weaker than an English speaker may expect
• the r in corrente is typically a stronger Portuguese r, not an English r

This is only an approximation, but it helps with the rhythm.

It can mean either, depending on context.

O desviador move a corrente can mean:

• a general fact: the derailleur moves the chain
• a description of what is happening now: the derailleur is moving the chain

Portuguese often uses the simple present in both ways, especially for general descriptions. If you want to make the ongoing action very explicit, Portuguese can also use another structure, but the simple present is perfectly normal here.

Yes. You could say:

A corrente é movida pelo desviador.

That means The chain is moved by the derailleur.

It is grammatically correct, but the active version is simpler and more natural in many everyday contexts:

O desviador move a corrente.

If the subject is already clear from context, Portuguese often leaves out subject pronouns such as ele. But here the subject is a full noun phrase, o desviador, and including it is the normal clear option.

If you removed it and just said Move a corrente, that could be understood differently depending on context, and it might even sound like a command: Move the chain.

So in this sentence, keeping O desviador is the best choice.