Learn Hardcore Dutch: Elk weekend trainen wij in het park.

Because elk is a fixed distributive pronoun meaning “each/every” and never takes -e. It always appears as elk before a singular noun, regardless of gender.

Why is weekend singular? Could I say alle weekenden?

Yes, you can say alle weekenden, but Dutch usually expresses “every …” with elk + singular noun. Alle is followed by a plural noun. Elk weekend (“every weekend”) is more idiomatic than alle weekenden (“all the weekends”).

Why does the verb trainen come before the subject wij in Elk weekend trainen wij in het park?

Dutch main clauses follow the V2 (verb-second) rule. When a time expression (Elk weekend) is fronted, the finite verb goes in second position and the subject follows it:

Elk weekend (fronted time)
trainen (finite verb)
wij (subject)

Could I say Wij trainen elk weekend in het park instead?

Absolutely. Both orders are correct and mean the same. Starting with Wij gives a neutral statement. Fronting Elk weekend puts more emphasis on the frequency.

Why doesn’t trainen end with -t like traint?

Verb endings depend on the subject. For wij (first-person plural) you use the stem/infinitive form without -t. Present-tense conjugation goes:

ik train
jij traint
hij/zij traint
wij trainen

Is wij mandatory? Can I use we or omit it?

You can replace wij with the informal we:

Elk weekend trainen we in het park.
However, Dutch generally requires an explicit subject pronoun in statements. Omitting it entirely is not standard.

Why is it in het park and not op het park?

In indicates being inside a location (the park). Op would imply “on top of” the park. If you meant “next to” the park, you’d use bij het park.

Can I front in het park instead? Like In het park trainen wij elk weekend?

Yes. You can start with a location adverbial, but you must still obey V2:

In het park trainen wij elk weekend.
In het park trainen we elke week.

What’s the difference between elk and iedere when saying “every”?

Both mean “every,” but:

elk is a pronoun and never changes form: elk weekend, elk jaar, etc.
iedere is an adjective and always takes -e before a noun: iedere dag, iedere maand, iedere weekend.
In practice elk weekend is more common, but iedere weekend is also correct.