Learn Hardcore French: Nous invitons nos voisins à déjeuner, et nous voulons confirmer l’heure par message. - We are inviting our neighbors for lunch, and we want to confirm the time by message.

pour le déjeuner treats lunch as a noun (the event): invite them for the lunch. It’s fine and common.
au déjeuner (à + le) also treats it as a specific lunch event; a bit more formal or business-like. All three can be correct; à déjeuner (verb) is the most neutral and idiomatic in everyday French.

Is « déjeuner » a verb here?

Yes. In à déjeuner, déjeuner is an infinitive verb meaning “to have lunch.” Note: Regional meanings differ. In France, déjeuner = lunch. In Québec/Belgium/Switzerland, déjeuner = breakfast, dîner = lunch, souper = dinner. So “invite to lunch” there would often be inviter à dîner (verb) or inviter au dîner (noun).

Can I say « on » instead of « nous »?

Yes. In spoken French, on is more common than nous for “we.”

Neutral: Nous invitons nos voisins…
Very natural spoken: On invite nos voisins… Remember: with on, the verb is 3rd person singular: on veut, on voudrait, etc. Using on is informal/neutral; nous is a bit more formal or written.

Does the present tense « nous invitons » mean now or the near future?

Both are possible. French often uses the present for near-future plans, especially with context.

Present as plan: Nous invitons nos voisins samedi.
Near future: Nous allons inviter…
Simple future: Nous inviterons… (more formal or distant)

Why « par message » and not « par un message » or « en message »?

For a communication channel, French usually uses par + medium with no article:

par message, par SMS, par e-mail/courriel, par WhatsApp. En message is not idiomatic here. Par un message is possible but less common; it emphasizes “by means of a (single) message.”

What’s the most natural way to say “by text” in different regions?

France: par SMS, par texto (both very common)
Québec: par message texte, also par SMS is understood
Neutral: par message (works broadly, slightly vague) Platform-specific: par WhatsApp / par Signal / par iMessage

Should there be a comma before « et »?

Generally no. Standard French style does not put a comma before et joining two clauses:
Nous invitons nos voisins à déjeuner et nous voulons confirmer l’heure par message.
A comma can appear to mark a deliberate pause, but it’s usually omitted.

Why « l’heure » and not « l’horaire » or « le temps »?

l’heure = the clock time (what time we meet). This is what you confirm.
l’horaire = a schedule/timetable (e.g., train schedule).
le temps = time in general (duration/weather), not a clock time here.
So confirmer l’heure is the idiomatic choice.

How do I include “to them” (confirm to them) with pronouns?

Use the indirect-object pronoun leur (to them):

Nous voulons leur confirmer l’heure (par message). If you also pronominalize “the time” (l’heure), it becomes:
With a modal: Nous voulons la leur confirmer.
Simple present: Nous la leur confirmons.
Pronoun order (before the verb/infinitive): me/te/se/nous/vous + le/la/les + lui/leur + y + en.

Is « Nous voulons confirmer… » polite enough when writing to neighbors?

It’s grammatically fine but can sound a bit direct. To soften:

Nous voudrions confirmer l’heure par message.
Pourrions-nous confirmer l’heure par message ?
Serait-il possible de confirmer l’heure par message ?
These sound more courteous.

How can I add “at our place” to the sentence?

Use chez nous:

Nous invitons nos voisins à déjeuner chez nous. You can add a day/time too: … dimanche à 12 h 30.

Should I use « voisins » or « voisines »?

voisins is masculine plural and serves as the default for mixed/unspecified groups.
If all neighbors invited are women, use voisines.
Inclusive writing sometimes shows voisin·e·s, but that’s a stylistic choice, not standard in everyday prose.

Any accent or apostrophe pitfalls here?

à has an accent grave; a (no accent) means “has.”
déjeuner has é.
l’heure uses elision (le → l’) because heure starts with a vowel sound (silent h).
So: à déjeuner, l’heure, not a dejeuner or le heure.

Are there useful pronunciation/liaison tips in this sentence?

Yes, common liaisons:

Nous invitons: pronounce a linking z sound → “nouz invitons.”
Nos voisins: linking z → “noz voisins.”
Optional light liaison in et nous in careful speech.
Keep the final consonants mostly silent except where liaison requires them; the “h” in heure is silent.

Why not « vouloir à/de confirmer »?

Because vouloir is a semi-auxiliary that takes a bare infinitive: vouloir + infinitif.

Correct: Nous voulons confirmer l’heure.
Incorrect: Nous voulons à confirmer / Nous voulons de confirmer.