A roda gira devagar.

Here, A is the definite article meaning the.

So:

• a roda = the wheel

Portuguese a can mean different things depending on context:

• a = the (feminine singular article)
• a = to (a preposition)

In A roda gira devagar, it is clearly the article because it comes before the noun roda.

If you wanted a wheel, you would say:

• uma roda

Because roda is a feminine noun in Portuguese.

Portuguese nouns usually have grammatical gender, so they take:

• o for masculine singular nouns
• a for feminine singular nouns

Since roda is feminine, you say:

• a roda

Its plural would be:

• as rodas = the wheels

Gira is the 3rd person singular present tense of the verb girar, which means to turn, to spin, or to rotate.

So:

• girar = to turn / to spin
• gira = turns / spins / rotates

In this sentence, a roda gira means:

• the wheel turns
• the wheel spins

Because girar is the infinitive form, like to turn or to spin in English.

In a normal sentence with a subject, Portuguese usually uses a conjugated verb:

• A roda gira = The wheel turns
• not A roda girar

So:

• girar = to spin
• gira = spins / turns

In Portuguese, you normally do not need a subject pronoun like it here.

The noun itself is already the subject:

• A roda = the wheel

So A roda gira already means The wheel turns.

You could say ela in some contexts, but it would usually be unnecessary or used for emphasis:

• A roda gira = normal
• Ela gira = It turns if the wheel is already understood from context

Devagar is an adverb. It means slowly.

It describes how the wheel turns:

• A roda gira devagar. = The wheel turns slowly.

Other examples:

• Ele anda devagar. = He walks slowly.
• Fala devagar. = Speak slowly.

That is a very normal position in Portuguese. Adverbs often come after the verb, especially in simple sentences.

So:

• A roda gira devagar. = natural and standard

You can sometimes move adverbs for emphasis, but the basic order here is the most neutral one.

In European Portuguese, gira is pronounced roughly like ZHEE-ruh.

A few key points:

• gi- sounds like zh in measure
• the r is a light tap sound
• the final a in European Portuguese is usually more reduced than in English

So gira does not start with a hard g as in gift. It is a soft sound:

• gira ≈ zhee-rə

A rough English-friendly pronunciation would be:

• uh ROH-duh ZHEE-ruh duh-vuh-GAHR

A few notes:

• A is usually reduced, more like uh
• roda has a rolled/tapped r sound at the start, and in European Portuguese the d can sound softer
• gira begins with the zh sound
• devagar has stress on the last syllable: -gar

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

Yes. As a form of girar, it means turns/spins here.

But giro / gira can also be an adjective in Portuguese, meaning something like nice, cute, or cool in some contexts.

For example:

• Que gira! = How cute! / How nice!

However, in A roda gira devagar, it is definitely the verb gira from girar, because it follows the subject a roda and is part of the sentence structure.

Yes. In European Portuguese, estar a + infinitive is a very common way to express an action in progress.

So:

• A roda gira devagar. = The wheel turns slowly / The wheel is turning slowly
• A roda está a girar devagar. = The wheel is turning slowly

The first sentence is simpler and more general. The second one emphasizes that the action is happening right now.

Usually, A roda means the wheel, so it sounds like a specific wheel or a wheel already known from the context.

But in some cases, Portuguese can use the definite article more generally than English does. Context decides a lot.

So in a basic learning sentence, the safest understanding is:

• a roda = the wheel

If you wanted a more general plural idea, you might say:

• As rodas giram devagar. = The wheels turn slowly.

The plural would be:

• As rodas giram devagar.

Changes:

• a → as
• roda → rodas
• gira → giram

So:

• A roda gira devagar. = The wheel turns slowly.
• As rodas giram devagar. = The wheels turn slowly.