In spoken and casual written Icelandic, the subject pronoun þú (you) rarely stands alone when it follows a verb. Instead, it attaches to the end of the verb, merging into a single word.
This cliticization (merging) is extremely common in questions (where the verb comes first) and commands.
The Suffixes: -ðu, -du, and -tu
When þú attaches to a verb, it transforms into a suffix. The first letter of the suffix changes to match the final sound of the verb it attaches to.
| Suffix | Used after | Examples in this lesson |
|---|---|---|
| -ðu | Vowels and voiced consonants (like r, g, f) | sérðu, keyrirðu, stígðu |
| -du | Voiced nasal/lateral consonants (l, m, n) | heyrdu (hear) |
| -tu | Voiceless consonants (like s, t, k, p) | manstu, settu, láttu |
Asking Questions
To ask a question in Icelandic, you invert the subject and the verb. Because the verb now comes first, þú immediately follows it and merges.
Notice how sér þú (do you see) becomes sérðu:
| Do you see the rearview mirror? | Sérðu baksýnisspegilinn? |
Because the verb manst (remember) ends in an s and a t, the attached pronoun takes the voiceless -tu ending, becoming manstu:
| Do you remember how you use the turn signal? | Manstu hvernig þú notar stefnuljósið? |
| Are you driving them home at a quarter past three? | Keyrirðu þau heim klukkan korter yfir þrjú? |
Giving Commands (The Imperative)
When you give instructions, such as during a driving lesson, you use the imperative mood. In Icelandic, imperative verbs are almost entirely built using these same attached þú endings on the stem of the verb.
Here, setja (to put) becomes settu, and stíga (to step) becomes stígðu:
| Put the car in gear and step on the clutch. | Settu bílinn í gír og stígðu á kúplinguna. |
| Stop and let the people cross the crosswalk. | Stoppaðu og láttu fólkið ganga yfir gangbrautina. |
Commands are often fired off quickly in sequence, especially when driving. Watch for how both the question forms and command forms use the exact same merging rules:
| Do you see the traffic light? Step on the brake now! | Sérðu umferðarljósið? Stígðu á bremsuna núna! |
| Look in the side mirror! | Horfðu í hliðarspegilinn! |