En français, « manger » est à l’infinitif.

En often means in when talking about languages:

• en français = in French
• en anglais = in English
• en espagnol = in Spanish

So En français is a very common way to say In French.

In French, language names are usually not capitalized.

So:

• le français = French
• l’anglais = English

This is different from English, where language names are capitalized.

The marks « » are French quotation marks, often called guillemets.

Here, manger is being mentioned as a word itself, not used normally in a sentence. English often does the same thing with quotation marks:

• “eat” is an infinitive
• “manger” est à l’infinitif

So the sentence is talking about the form of the word manger.

In French, the infinitive form of a verb is written without any extra word in front of it.

Examples:

• manger = to eat
• parler = to speak
• finir = to finish

English usually uses to before the infinitive, but French does not. So manger by itself is the infinitive.

Literally, it means something like is in the infinitive or is in the infinitive form.

French often uses être à + grammatical form to describe the form of a word:

• est à l’infinitif = is in the infinitive
• est au passé = is in the past
• est au pluriel = is in the plural

So this is a natural French way to describe grammar.

Because à l’infinitif is a fixed grammatical expression meaning in the infinitive form.

Compare:

• Le verbe est à l’infinitif. = The verb is in the infinitive form.
• Le verbe est au présent. = The verb is in the present tense.

So à here helps express the idea of form/state.

Because infinitif begins with a vowel sound, French uses elision:

• le infinitif becomes l’infinitif

This is very common:

• le ami → l’ami
• la école → l’école
• le infinitif → l’infinitif

So à l’infinitif is just à + l’infinitif.

Here, infinitif is functioning as a noun in a grammar expression.

It refers to the infinitive form.
So:

• l’infinitif = the infinitive

French grammar terms often work like this:

• le présent = the present
• le passé = the past
• l’infinitif = the infinitive

The comma separates the introductory phrase En français from the rest of the sentence.

It is similar to English:

• In French, “manger” is in the infinitive.

The comma is not always absolutely necessary in every short sentence, but it is very normal here and makes the sentence clearer.

Yes, absolutely.

That version is a little more explicit because it says the verb manger:

• Le verbe manger est à l’infinitif.

The original sentence is also natural because it is already obvious that manger is being discussed as a verb form.

It is pronounced roughly like mahn-zhay.

A few useful points:

• man- sounds like mahn
• -ger here sounds like zhay
• the g is soft, like the s in measure

So manger does not sound like the English noun manger.

Manger is a regular -er verb, which is the most common verb type in French.

Its infinitive ends in -er, like:

• parler = to speak
• aimer = to like/love
• chanter = to sing

So this sentence could also help a learner recognize manger as a basic infinitive verb form.