Learn Hardcore Norwegian: Tom lurer på om lommeboken min alltid er så rotete. - Tom wonders whether my wallet is always that messy.

lurer på is the present tense of the verb å lure på, which literally means “to wonder on/about.” In English we’d simply say “to wonder.” Here, Tom lurer på translates as “Tom wonders” or “Tom is wondering.”

Why is there an om after lurer på, and what role does it play?

The word om introduces a subordinate clause meaning “whether” or “if.” When you use å lure på to express “wondering whether…,” you follow it with om. So Tom lurer på om … = “Tom wonders whether…”

Why is the possessive min placed after lommeboken, instead of before it?

In Norwegian you normally put possessive pronouns after the noun: lommeboken min literally “the wallet my,” which is equivalent to English “my wallet.” You can say min lommebok if you want to emphasize “my” over “wallet,” but the unmarked, everyday order is lommeboken min.

Why does lommeboken already have a definite ending -en if min also marks possession?

Norwegian uses “double definiteness” with possessives:

lommebok (a wallet)
lommeboken (the wallet)
lommeboken min (the wallet of mine / my wallet)
The -en is the standard definite article for a common-gender noun, and min shows it belongs to “me.”

Where does the adverb alltid (“always”) go, and why is it before er?

In a subordinate clause introduced by om, Norwegian follows subject–adverb–verb order, so the sequence is:
Subject (lommeboken min) → Adverb (alltid) → Verb (er) → Rest (så rotete).
English puts adverbs in various places (“my wallet is always so messy”), but Norwegian often places them right before the verb in subordinate clauses.

What does så add to rotete, and can it be omitted?

Here så means “so” as an intensifier (“so messy”). If you drop så, you still get a correct sentence:
“Tom lurer på om lommeboken min alltid er rotete.”
But that simply states “always messy” without the extra emphasis that så provides.

Why is the adjective rotete not another form like rotet or rotet?

Adjectives in Norwegian agree in number, gender, and definiteness. rotete is the common-gender indefinite form used in predicate position after er. If the noun were neuter, you’d see rotet (e.g. brevet er rotet). Here, because lommebok is common gender, the predicate adjective stays rotete.

Could you say min lommebok instead of lommeboken min, and is there any nuance?

Yes, you can say min lommebok. It’s grammatically correct but puts a bit more emphasis on my (as if contrasting with someone else’s wallet). The typical neutral phrasing is lommeboken min, which simply states ownership without special stress.