Learn Hardcore Icelandic: Við klöppum fyrir liðið okkar.

Klöppum is the 1st person plural present indicative of the verb klappa (“to clap; to applaud”). The ending -um tells you the subject is we, and in this conjugation the u in -um triggers an i-umlaut (a stem-vowel change) on a → ö.

Why does the a in klappa change to ö in klöppum?

In Icelandic many verbs with a short a in the stem undergo i-umlaut when you add plural endings like -um. The u of the ending reaches back and mutates a to ö, so klappa → klöppum for we clap.

What does fyrir mean here, and which case does it govern?

Here fyrir means for (as in cheering for someone). In this usage fyrir governs the accusative case, so liðið (“the team”) is the accusative form of liður.

Where is the definite article in liðið, and why isn’t there a separate word for “the”?

Icelandic marks definiteness with a suffix on the noun rather than a separate word. The base noun is liður (“team”), and the definite accusative singular is liðið (“the team”).

Why does okkar (“our”) come after liðið, and what case is it?

Possessive pronouns in Icelandic follow the noun they modify. Okkar is the genitive personal pronoun for we, so liðið okkar literally means “the team of us” = “our team.”

Do you have to include við (“we”) here, or could you leave it out?

Because klöppum is already marked for 1st person plural, you can omit við in casual or emphatic contexts (e.g. Klöppum fyrir liðið okkar!). Including við adds clarity or emphasis: Við klöppum… = “We clap…”

How would I pronounce Við klöppum fyrir liðið okkar?

A rough IPA transcription:
[vɪːð ˈklœhpʏm ˈfɪːrɪr ˈliːðɪ ˈɔkːar]

Approximate guide in English sounds:
“VEETH KLUHP-um FEER-ir LEETH-ith OK-kar”

ð like the “th” in this (voiced)
ö like French eu in bleu
short u in -um is a front rounded ʏ (similar to German ü in Müll)