Ma copine vient en trottinette.

It can mean either one. Ma copine may mean:

• my girlfriend
• my female friend

French often relies on context to make the difference clear. In everyday speech, ma copine is very commonly understood as my girlfriend, but it does not always have to be romantic.

Because copine is a feminine noun. In French, the possessive adjective agrees with the gender and number of the thing possessed, not with the owner.

So:

• mon copain = my boyfriend / my male friend
• ma copine = my girlfriend / my female friend

Here, copine is feminine singular, so ma is correct.

Vient is the present tense of the verb venir (to come).

It is the third-person singular form, used with:

• il
• elle
• singular nouns like ma copine

So:

• je viens = I come / I am coming
• tu viens = you come / you are coming
• elle vient = she comes / she is coming

It can mean both, depending on context.

French present tense often covers both:

• she comes
• she is coming

So Ma copine vient en trottinette could mean:

• My girlfriend comes by scooter
• My girlfriend is coming by scooter

English chooses between simple present and present continuous more often than French does.

French often uses en to express the means of transport.

Examples:

• en voiture = by car
• en train = by train
• en avion = by plane
• en trottinette = by scooter / on a scooter

So en trottinette tells you how she is coming.

Because with many forms of transportation, French normally uses en, not à.

For example:

• en bus
• en métro
• en voiture
• en trottinette

French does use à in some travel expressions, especially with things you ride more directly or straddle, such as:

• à vélo = by bike
• à moto = by motorcycle
• à pied = on foot

So trottinette belongs with the en pattern here.

In many transport expressions, French uses en + noun without an article.

So you say:

• en voiture
• en train
• en trottinette

not:

• en une trottinette
• en la trottinette

This is just the normal idiomatic pattern for means of transport.

Trottinette usually means a scooter, especially a kick scooter or electric scooter, depending on context.

So en trottinette usually means something like:

• by scooter
• on a scooter

If you want to be more specific, French can also say things like:

• trottinette électrique = electric scooter

Yes. It follows a very standard French pattern:

subject + verb + expression of manner/transport

So:

• Ma copine = subject
• vient = verb
• en trottinette = how she comes

This is a completely natural basic sentence in French.

Yes. That is also correct, but it is slightly different in meaning.

• vient focuses on coming
• arrive focuses on arriving

So:

• Ma copine vient en trottinette = My girlfriend is coming by scooter.
• Ma copine arrive en trottinette = My girlfriend is arriving on a scooter.

Both are natural; they just emphasize slightly different things.

Vient is pronounced roughly like vyan in English approximation, with a nasal vowel at the end.

A few important points:

• the v is like English v
• ien makes a nasal sound
• the final t is normally silent

So you do not pronounce it like vee-ent.

Not always. The French present tense is flexible. Depending on context, it can describe:

• something happening now
• a usual habit
• a near future event

So Ma copine vient en trottinette could mean:

• she is coming right now on a scooter
• she usually comes by scooter

Context tells you which meaning is intended.