J’ai failli manquer le train ce matin.

Because faillir is commonly used as a semi-auxiliary meaning to almost do something.

So the pattern is:

subject + avoir + failli + infinitive

In this sentence:

• j’ai = I have
• failli = almost
• manquer = to miss

So j’ai failli manquer literally works like I almost missed.

This is one of the most common ways in French to express a near-event.

Examples:

• J’ai failli tomber. = I almost fell.
• Il a failli oublier. = He almost forgot.
• Nous avons failli arriver en retard. = We almost arrived late.

Because the speaker is talking about a specific event that happened this morning: they came close to missing the train at one particular moment.

French usually uses the passé composé for:

• completed events
• specific events in the past
• one-time actions

So j’ai failli manquer le train ce matin fits that perfectly.

Using the imperfect here would sound unusual in normal conversation. The idea is not I was almost missing the train, but rather I almost missed the train at a specific moment.

Not in this sentence.

Although faillir is historically related to the idea of failing, in modern French this structure usually means to nearly / to almost.

So here, j’ai failli manquer le train means:

• I almost missed the train
• I came close to missing the train

It does not mean I failed to miss the train.

That is an important point for English speakers, because the literal pieces can be misleading.

Because manquer has more than one pattern in French.

Here, manquer + direct object means to miss in the sense of not catch / not get / not be there in time for something.

So:

• manquer le train = to miss the train
• manquer le bus = to miss the bus
• manquer son rendez-vous = to miss one’s appointment

But there is another pattern:

• manquer à quelqu’un = to be missed by someone / to be lacking to someone

For example:

• Tu me manques. = I miss you.
  Literally: You are missing to me.

So in your sentence, le train is the thing being missed, which is why French uses manquer le train.

Yes, you could, and it would be understood.

But j’ai failli manquer le train is especially natural and idiomatic for I almost missed the train.

A useful difference is:

• faillir + infinitive = a very standard way to say almost did
• presque + verb = also possible, but often feels a bit more directly like nearly

So both can work:

• J’ai failli manquer le train.
• J’ai presque manqué le train.

Many learners will hear faillir + infinitive very often in this kind of sentence.

Yes.

You can say:

• J’ai failli rater le train ce matin.

That also means I almost missed the train this morning.

The difference is mainly one of tone:

• manquer is neutral and very standard
• rater is also very common, often a bit more everyday or informal depending on context

Both are widely used in spoken French.

Because French often places time expressions like ce matin, hier, demain, la semaine dernière, etc. at the end of the sentence when giving extra information about when something happened.

So:

• J’ai failli manquer le train ce matin. = very natural

You can also move it:

• Ce matin, j’ai failli manquer le train.

That version puts more emphasis on this morning.

So both are correct:

• end position = neutral, very common
• front position = highlights the time

Failli is pronounced approximately like fah-yee.

A few pronunciation notes:

• ai in fai- sounds like eh in many accents of French
• ll in failli gives a y sound here
• so it is roughly /fa-yi/

In the full sentence:

J’ai failli manquer le train ce matin

A rough English-friendly pronunciation might be:

zhay fah-yee mahn-kay luh trahn suh ma-tan

Not exact, but helpful as a starting point.

French usually uses an article where English sometimes does too, but in transport expressions like this, French definitely keeps it:

• manquer le train
• prendre le train
• attendre le bus
• rater l’avion

So le train means the train in the specific practical sense: the train you were supposed to catch.

French normally does not drop the article here.

Yes: j’ai is simply je + ai.

French changes je ai to j’ai because je becomes j’ before a vowel sound. This is called elision.

So:

• je ai ❌
• j’ai ✅

This happens all the time:

• j’aime
• j’habite
• j’écoute
• j’ai

So in your sentence, j’ai failli is just the normal contracted form.

No, not here.

Failli is the past participle of faillir, and in this sentence it stays failli.

That is the normal form you should learn and use:

• J’ai failli tomber.
• Elle a failli partir.
• Ils ont failli perdre.

For most learners, the important thing is simply to remember the fixed-looking pattern:

avoir + failli + infinitive

That pattern will serve you well in everyday French.