Learn Hardcore Finnish: Tilaan taksin nyt, sehän on kätevää. - I will order a taxi now; after all, it is convenient.

It’s the present tense of tilata (to order), 1st person singular. Finnish uses the present for near-future actions too, so here it naturally reads as I’ll order (now).

Why is it taksin and not taksi?

Taksin is the total object (genitive-accusative) form. In an affirmative sentence where the action is seen as complete or results in a whole, countable thing, the object is in this -n form: Tilaan taksin. With negatives or ongoing/indeterminate actions, you’d use the partitive: En tilaa taksia.

Could I say Tilaan taksia nyt? What would that mean?

Yes. Tilaan taksia (partitive object) suggests an ongoing process, attempt, or indeterminate outcome: I’m in the process of ordering a taxi / I’m trying to get a taxi. Tilaan taksin presents it as a completed, definite order.

Why is kätevää in the partitive, not kätevä?

Here se refers to the whole preceding action (ordering a taxi), an abstract idea. Predicative adjectives can appear in the partitive to describe an abstract/indefinite quality: Se on kätevää = That is convenient (as a quality). Se on kätevä would describe a concrete, countable thing (e.g., a tool) as handy.

What does sehän add to the meaning?

-hän/-hän is a clitic that softens or highlights shared/obvious information: kind of like after all, you know, as we both know, indeed. Sehän on kätevää nudges the listener to agree that it’s obviously convenient.

Is the clitic -hän the same as the pronoun hän (he/she)?

No. They just look the same. -hän/-hän is an enclitic particle that attaches to the first word of a clause. Hän is the personal pronoun for people in standard Finnish.

Why is it sehän with ä, not sehan?

Vowel harmony. The clitic is -hAn, realized as -han or -hän depending on the vowels of the host word. With se (front vowel e), it becomes -hän: sehän.

Can -hän attach somewhere else in the clause?

Yes; it typically attaches to the first element of the clause and marks that element as topical/shared. Variants:

Sehän on kätevää (it is, as we know, convenient).
Onhan se kätevää (it is indeed convenient; focuses the verb assertion).
Nythän tilaan taksin (now, as you see, I’m ordering a taxi).
The nuance shifts with placement.

Why is there a comma before sehän on kätevää?

Finnish commonly separates independent clauses with a comma even without a conjunction. You could also use a dash for a stronger afterthought feel: Tilaan taksin nyt — sehän on kätevää.

What’s the difference between Tilaan taksin nyt and Tilaan nyt taksin?

Both are grammatical. Finnish tends to put the main focus toward the end:

Tilaan taksin nyt highlights the timing (now).
Tilaan nyt taksin more readily highlights the choice of a taxi (as opposed to another option), with now as background time info.

Could I just say Se on kätevää without -hän?

Yes. Without -hän it’s a neutral statement. Adding -hän makes it sound like a friendly reminder or shared conclusion: it is convenient, after all.

What nuances do tilata taksi, soittaa taksi, ottaa taksi, and varata taksi have?

tilata taksi: arrange/order a taxi via phone/app (general).
soittaa taksi(n): call a taxi (by phone).
ottaa taksi(n): take a taxi as your mode of transport.
varata taksi(n): book a taxi in advance for a set time.

Is this sentence formal or informal?

It’s neutral-to-informal. The clitic -hän and the comment-like second clause are typical of spoken style. In formal text you’d more often see a plain Se on kätevää or avoid the clitic.

How do I pronounce sehän and kätevää?

Stress the first syllable in each word: SE-hän, KÄ-te-vää. In kätevää, the final ää is a long vowel; make it noticeably longer than a single ä.

Why does tilaan have two a’s?

Tilata is a type 4 verb (-ata/-ätä). In the present, you drop -ta and add endings: minä tilaan, sinä tilaat, hän tilaa, etc. That’s why you see the double a in tilaan.

Why se and not hän or tämä here?

Se refers back to the situation or action (ordering a taxi). Hän is for people in standard Finnish. Tämä means this (specific, proximal thing). Here we’re commenting on the preceding action in general, so se is the natural choice.

Does nyt ever mean anything other than now?

Yes, nyt can be a discourse particle (e.g., softening or urging: come on, now then). In this sentence it’s the literal time adverb meaning now.