Learn Hardcore Finnish: Joka keskiviikko lähetän pitkän tekstiviestin äidille. - Every Wednesday I send a long text message to my mother.

In Finnish you can omit the pronoun when the subject is clear from the verb ending. Here lähetän has the personal ending -n, which marks first-person singular, so you know the subject is I. Adding minä (“I”) would be redundant unless you want extra emphasis.

What does Joka keskiviikko mean and why is it used instead of keskiviikkona?

Joka keskiviikko literally means every Wednesday. It expresses a recurring action each Wednesday.

keskiviikkona is the essive case (“on Wednesday”), which usually refers to one specific Wednesday or describes something happening on Wednesday in a more one-off sense.
For regular weekly repetition Finnish prefers joka
- nominative (joka keskiviikko) or the adverbial form keskiviikkoisin.

Could we use keskiviikkoisin instead of joka keskiviikko?

Yes. Keskiviikkoisin is an adverb meaning “on Wednesdays” (habitually). The sentence becomes:
Keskiviikkoisin lähetän pitkän tekstiviestin äidille.
The meaning remains “Every Wednesday I send a long text message to (my) mother.”

Why is tekstiviestin in that form and not in the partitive case?

Tekstiviestin is the accusative/genitive singular form. You use the full object form (with -n) when the action is viewed as whole or complete—in this case sending the entire message.
If you wanted to express an incomplete or ongoing action (send some of a message), you’d use the partitive:
lähetän tekstiviestiä.

Why is the adjective pitkän inflected with -n?

Adjectives agree with the nouns they modify in case and number. Here pitkä (“long”) modifies tekstiviesti in the accusative/genitive singular, so pitkä takes its corresponding form pitkän.

What case is äidille and what does the -lle suffix indicate?

Äidille is in the allative case, marked by the suffix -lle, which denotes direction or “to” a recipient. So äidille means to (the) mother.

Why can we say äidille instead of minun äidilleni?

Context often makes it clear whose mother you mean, so äidille suffices. If you want to be explicit or emphasize “my mother,” you can use the possessive suffix -ni:
lähetän äidilleni pitkän tekstiviestin.

Can the word order be changed, and if so, what changes?

Yes. Finnish has relatively free word order for emphasis or focus. For example:
– Äidille lähetän joka keskiviikko pitkän tekstiviestin. (Emphasizes to mother)
– Pitkän tekstiviestin lähetän äidille joka keskiviikko. (Emphasizes the long text message)
The basic meaning stays the same; only the emphasis shifts.

What person and tense is lähetän and how do we know it means “I send”?

Lähetän is present tense, first-person singular of the verb lähettää (“to send”). The ending -n indicates I, and the lack of any past marker means it’s present/perfective habitual (“I send” or “I am sending”).