Learn Hardcore Spanish (Latin America): ¿Asistirás al seminario conmigo o prefieres quedarte en casa? - Will you attend the seminar with me, or do you prefer to stay at home?

asistirás is the second person singular (tú) simple future of asistir. In Spanish, you form the simple future by adding endings directly to the infinitive. For regular ‑ir verbs like asistir:

Yo: asistir + é = asistiré
Tú: asistir + ás = asistirás
Él/Ella/Ud.: asistir + á = asistirá
… and so on.

Why is al used before seminario instead of a el?

In Spanish, a + el always contracts to al. You never say a el. So:
a + el seminario = al seminario.

Why is conmigo used instead of con yo or con mí?

Spanish has built-in forms for “with me” and “with you”:

conmigo = with me
contigo = with you
Using con yo or con mí is grammatically incorrect.

What is the function of te in quedarte and why is it attached to the infinitive?

Quedarte comes from the reflexive verb quedarse (to stay). Reflexive verbs require a pronoun (me, te, se, etc.) that matches the subject. Here, te indicates tú. In Spanish, when a verb is in the infinitive, any reflexive or object pronoun attaches to its end:
quedarse → quedarte (for you to stay).

Why is prefieres in the present tense while the other verb is in the future?

Spanish allows mixing tenses when it makes sense. Here:

Asistirás (future) asks “Will you attend…?”
prefieres (present) states your current preference: “or do you prefer to stay home?”
This mirrors English: “Will you go or do you prefer to stay home?”

Which subject pronoun is implied in asistirás and prefieres, and why is it omitted?

Both verbs are in the tú form:

asistirás = “you will attend”
prefieres = “you prefer”
Spanish often drops the pronoun because the verb ending already tells you who the subject is.

Why are there inverted question marks at the beginning and regular ones at the end?

Spanish questions always start with ¿ and end with ?. The inverted mark signals at the very beginning that what follows is a question.

Can we use irás al seminario instead of asistirás al seminario, and what's the difference?

Yes. Ir means “to go,” while asistir means “to attend” an event.

irás al seminario focuses on traveling to the seminar’s location.
asistirás al seminario emphasizes participating in the event itself.
Both are correct, but asistir is more precise for events.

What gender is seminario, and how do you know?

Seminario is masculine. Most Spanish nouns ending in -o are masculine. You also see this in al seminario (a + el), confirming el seminario.