Learn Hardcore Spanish (Spain): Después de cenar, fregamos las tazas porque el lavavajillas está lleno. - After dinner, we wash the cups because the dishwasher is full.

With an infinitive: Después de cenar = After dining/eating dinner.
With a noun: Después de la cena = After the dinner. “Después cenar” and “Después la cena” are incorrect. You can also use “después” alone as an adverb: Cenamos y después fregamos.

Why not “Después de cenando”?

After a preposition (like de) Spanish uses the infinitive, not the gerund. So it must be después de cenar, not “después de cenando.”

Can I say “Tras cenar” or “Luego de cenar” instead?

Tras cenar is a perfectly natural alternative in Spain.
Luego de cenar is common in much of Latin America; in Spain it sounds more Latin American. All three mean “after eating dinner.”

What tense is “fregamos”? Is it present or past?

Fregamos can be either present (we wash) or preterite (we washed) for -ar verbs in the 1st-person plural; context disambiguates.

In your sentence, está lleno suggests present/habitual: “After dinner, we (usually) wash...”
To make it clearly past, add a time word or pick a different form:
- Anoche, después de cenar, fregamos las tazas... (preterite, last night)
- Hoy, después de cenar, hemos fregado las tazas... (present perfect; very natural in Spain for “today” events)

Why “fregar” and not “lavar”?

In Spain, fregar is the common verb for washing dishes by hand and for scrubbing floors: fregar los platos/el suelo. Lavar is more general (“to wash” hands, clothes, car), and in Latin America people often say lavar los platos. In Spain, lavar los platos is understood, but fregar sounds more native.

Is “friegamos” ever correct?

No. Fregar is an e→ie stem-changer, but not in nosotros/vosotros. Present indicative:

friego, friegas, friega, fregamos, fregáis, friegan Preterite: fregué, fregaste, fregó, fregamos, fregasteis, fregaron (note fregué with -gué).

Why “las tazas”? Could it be “unas tazas” or no article?

Las tazas refers to specific cups the speakers have in mind (very common in Spanish).
Unas tazas = some cups (not specific).
Dropping the article (“fregamos tazas”) sounds odd here. Spanish uses definite articles more than English in these contexts.

Does “tazas” mean all dishes? What about “vasos,” “copas,” and “platos”?

Taza = cup with a handle (often for hot drinks; a “mug” is usually a type of taza, sometimes taza grande or tazón).
Vaso = glass (no stem).
Copa = stemmed glass (wine, champagne).
Plato(s) = plate(s), but fregar/lavar los platos is a set phrase meaning “do the dishes” (all dishware).
Vajilla = dishware set.

Why is it “porque” and not “por qué”?

porque = because: Fregamos... porque el lavavajillas está lleno.
por qué = why?: ¿Por qué fregáis...?
el porqué (noun) = the reason: No entiendo el porqué.
por que = “por” + relative “que” (rare; usually replaced by por el que/la que).

Is “lavavajillas” one word, and what gender is it?

Yes, lavavajillas is one word and masculine: el lavavajillas. Its plural is invariable: los lavavajillas. In Spain, it refers to the dishwasher; it can also mean dishwashing detergent in context. A common Latin American synonym is lavaplatos.

Why “está lleno” and not “es lleno”? And why “lleno” (not “llena”)?

Use estar with states/conditions: está lleno = it is (currently) full. Ser lleno is generally not used.
Lleno agrees with el lavavajillas (masculine singular). If the noun were feminine singular, you’d use llena; for plural masculine, llenos; plural feminine, llenas.

Do I need “de” after “lleno”?

Only if you specify what it’s full of:

General state: está lleno.
Specified contents: está lleno de platos sucios.

Can I put the reason first?

Yes. You can say:

Como el lavavajillas está lleno, fregamos las tazas. (Very natural at sentence start)
Ya que el lavavajillas está lleno, fregamos...
Porque el lavavajillas está lleno, fregamos... (also possible) When the cause goes second, porque is the default: Fregamos... porque...

Is the comma after “Después de cenar” necessary? And do I put a comma before “porque”?

After a fronted time clause like Después de cenar, Spanish normally uses a comma.
Don’t put a comma before porque: ... fregamos las tazas porque ... (no comma).

Could I replace “las tazas” with a pronoun? Where does it go?

Yes, las (feminine plural direct object):

Before a conjugated verb: Después de cenar, las fregamos porque...
Attached to an infinitive/gerund/affirmative command: Después de cenar, vamos a fregarlas. / Estamos fregándolas. / ¡Frégalas!