Adjective + -tu

Becoming: Verbs in -tu

Level 4

Basque makes many verbs by adding -tu to an adjective or noun: zahar → zahartu (old, to age), bero → berotu (hot, to heat up). Asko zahartu da means He has aged a lot.

How It Works

Forming the verb.

  • After a vowel or most consonants, add -tu: garbi → garbitu (to clean), handi → handitu (to grow, to enlarge), bero → berotu (to heat up), zahar → zahartu (to age), hori → horitu (to turn yellow)
  • After n or l, it becomes -du: ilun → ilundu (to get dark), euskaldun → euskaldundu (to become a Basque speaker)
  • After tz or ts, the spelling changes to z or s: hotz → hoztu (to cool down), aberats → aberastu (to get rich)

Nouns work the same way: lotsa → lotsatu (to feel embarrassed), haserre → haserretu (to get angry).

Becoming or making. Choose the auxiliary by meaning. When the subject changes by itself, use da: Esnea berotu da (The milk has warmed up). When someone brings the change about, use du with an ergative doer: Esnea berotu dut (I have heated the milk). This is the same switch as in Atea ireki da. Some verbs lean one way: zahartu (to grow old) takes da, while garbitu (to clean) usually has a doer and takes du.

All the verb forms. Because the new word is a normal participle, it has the usual imperfective and future forms: Egunero garbitzen dut sukaldea (I clean the kitchen every day). Kafea hoztuko da (The coffee will get cold).

Many borrowed verbs have the same shape, such as bukatu (to finish) and pentsatu (to think): -tu is simply the most common participle ending in Basque.

Examples (6)

  1. Asko zahartu da azken urteotan.

    He has aged a lot in recent years.

    zahar (old) + -tu; the change happens to the subject, so da.

  2. Gela garbitu dut.

    I have cleaned the room.

    garbi (clean) + -tu; someone does the cleaning, so du.

  3. Herria asko handitu da.

    The town has grown a lot.

  4. Kafea hoztu da.

    The coffee has gone cold.

    hotz + -tu is spelled hoztu.

  5. Zerua ilundu da.

    The sky has darkened.

    -du after n: ilun, ilundu.

  6. Esnea berotu dut.

    I have heated the milk.

    Compare Esnea berotu da, The milk has warmed up.

Common Mistakes

  • Using du when the subject changes by itself.

    Aita asko zahartu du.
    Aita asko zahartu da.

    To say that Dad has aged, the change happens to him by itself, so zahartu takes da. With du, the sentence says that something has aged him, as in Urteek zahartu naute (The years have aged me).

  • Keeping tz before the t of -tu.

    Kafea hotztu da.
    Kafea hoztu da.

    Before -tu, tz is written z and ts is written s: hotz, hoztu; aberats, aberastu.

  • Using -tu after n.

    Zerua iluntu da.
    Zerua ilundu da.

    After n and l the ending is -du: ilun, ilundu. The imperfective is iluntzen, which may be why learners write -tu.

How It Connects

Tap a pattern to see what it builds on and what it leads to.

Adjective + -tuLevel 4Becoming: Verbs in -tu

Learn This First

Verbs from adjectives need the participle and adjectives.