Learn Hardcore Turkish: Bu kitap ucuz; iki tane alalım. - This book is cheap; let’s buy two.

tane is a classifier meaning “unit/piece.” It emphasizes counting discrete items.
With a noun present, it’s optional: iki kitap and iki tane kitap both mean “two books.”
When the noun is omitted, tane makes the counting sound natural: İki tane alalım is very common; İki alalım also occurs, but iki tane feels clearer and more colloquial.
In this sentence, iki tane implies “two copies (of this book).”

Why is the verb alalım used, and what form is it?

alalım is the 1st person plural hortative/optative: “let’s buy/take.”
Formation: al- (take/buy) + -a- (optative marker, obeys vowel harmony) + -lım (1st person plural).
Negative: almayalım (“let’s not buy”).
Suggestion as a question: alalım mı? (“shall we buy?”).

Does almak mean “to take” or “to buy”?

Both. almak means “to take” in general, but in shopping contexts it commonly means “to buy.” Here, given the context of a book’s price, it means “buy.” A more explicit “buy” is satın almak (e.g., iki tane satın alalım).

Why is there no -i accusative ending on iki tane?

Turkish marks definite/specific direct objects with accusative, but leaves indefinite ones unmarked.

Indefinite: İki tane alalım. (no accusative; just “let’s buy two.”)
Definite/specific from a known set: İki tanesini alalım. (“let’s buy two of them.” Here -si is possessive “of them,” and -ni is accusative.)
If you mean specifically “these two,” use a demonstrative: Bu ikisini alalım.

Is İki taneyi alalım correct?

It’s not the best form. When tane stands for “of them,” standard Turkish uses the possessive: iki tanesini (alalım). If you point to specific items, a cleaner option is Bu ikisini alalım (“let’s take these two”). Colloquially you might hear iki taneyi, but the possessive form iki tanesini is the norm.

Could I say Bu kitaptan iki tane alalım?

Yes—very natural. -DAn here (“from/of”) marks a partitive-like meaning: Bu kitaptan iki tane alalım = “Let’s buy two copies of this book.” Your original sentence omits bu kitaptan because it’s clear from context.

Why is kitap singular after iki?

After numbers, Turkish uses the bare singular form:

iki kitap (not “iki kitaplar”)
on elma, üç gün If you include tane, it’s still singular: iki tane kitap.

Is the semicolon (;) normal here?

Yes. It neatly links two related independent clauses: a reason and a suggestion. A period would also be fine:

Bu kitap ucuz. İki tane alalım. A comma is common in casual writing but less standard than a semicolon or period in this context.

What’s the difference between ucuz and ucuzdur?

ucuz: plain, neutral statement (“is cheap”).
ucuzdur: adds formality, generalization, or an air of certainty/inference. Here, Bu kitap ucuz is the most natural choice.

Could I use şu or o instead of bu?

bu = this (near the speaker)
şu = that (near the listener or in shared sight, a bit farther)
o = that (farther away / not in sight) So you could say Şu kitap ucuz; iki tane alalım if you’re indicating a book a bit away, or O kitap ucuz… for something distant or not visible.

Do I need to say Biz?

No. Turkish is pro-drop, and the ending -lım already encodes “we.” Biz can be added for emphasis: Biz iki tane alalım (“Let’s (we) buy two.”).

Can I change the word order?

Within the suggestion: İki tane alalım is the default (quantity before the verb).
You can front elements for emphasis: Alalım iki tane (emphasis on “let’s buy”) sounds stylistic/colloquial.
Clause order can be swapped for discourse effect: İki tane alalım; bu kitap ucuz. (leading with the suggestion).

Is there a difference between iki tanesini alalım and ikisini alalım?

ikisini = “two of them/both (of them).” It doesn’t highlight “units,” just the count.
iki tanesini = “two pieces/units of them,” emphasizing discrete, countable items—useful when talking about multiple copies of the same thing (like books). In many contexts they overlap, but iki tanesini better fits “two copies.”

What about adet vs tane?

Both mean “unit/piece,” but:

tane is everyday and colloquial.
adet is more formal/technical (in invoices, orders, etc.). So in speech: iki tane; on a receipt: 2 adet.