Lesson 6: Stem-Changing & Irregular Verbs

In Lesson 4 you learned the tidy regular verbs. Now meet the rebellious ones. In many Spanish verbs the vowel inside the stem changes when the stress falls on it: pensar (to think) becomes *pienso*, not *penso*. These are called stem-changing verbs or "boot verbs", because if you draw a line around the changed forms on a conjugation chart, the shape looks like a boot. Other verbs are irregular in the yo form only, and a famous few — ir, dar, ver — march entirely to their own drum. Master these patterns and you can use the most common verbs in the language, because the irregular verbs are the ones people use most.

The three boot patterns

The change happens in all forms except nosotros (and vosotros): the stressed stem is inside the boot; the quiet ending-stressed forms stay outside it. More key verbs: e→ie — querer (to want), empezar (to begin), entender (to understand), cerrar (to close); o→ue — dormir (to sleep), volver (to return), encontrar (to find), costar (to cost); e→i — servir (to serve), repetir (to repeat), seguir (to follow/continue). Jugar (to play) is unique: u→ue — *juego, juegas, juega, jugamos, juegan*.

Yo-go verbs: irregular only in "I"

These verbs add a g in the yo form but are otherwise regular (some also have a stem change):

Watch compound verbs built on these: mantener (to maintain) behaves like tener, proponer like poner, detener like tener.

Three total rebels: ir, dar, ver

Ir a + infinitive is the everyday near future: *Voy a viajar mañana* — I am going to travel tomorrow. Learn this pattern today and you can talk about plans in almost any situation.

Example sentences

• Quiero un café, por favor. — I want a coffee, please.
• ¿Puedes ayudarme? — Can you help me?
• Ellos duermen ocho horas. — They sleep eight hours.
• Nosotros no entendemos la pregunta. — We don't understand the question. (nosotros = outside the boot: entendemos)
• Tengo prisa; salgo ahora. — I'm in a hurry; I'm leaving now.
• Ella pide la cuenta. — She asks for the bill.
• Voy a estudiar esta noche. — I'm going to study tonight.
• ¿Cuánto cuesta este libro? — How much does this book cost?
• Los niños juegan en el parque. — The children play in the park.

Dialogue: plans for Saturday

Lucía: ¿Qué quieres hacer el sábado? Pablo: No sé. ¿Quieres ir al cine? Lucía: Prefiero el museo. Empieza una exposición nueva. Pablo: Bueno. ¿A qué hora cierra el museo? Lucía: Cierra a las ocho. Pero primero almorzamos, ¿no? Pablo: Sí. Conozco un restaurante cerca. Sirven una paella excelente. Lucía: Perfecto. Entonces, ¿volvemos a casa a las nueve? Pablo: De acuerdo. Yo pido los billetes por internet.

Comprehension questions: 1. What two activities do they discuss? 2. Which one do they choose, and why does Lucía prefer it? 3. What does Pablo offer to do at the end?

Answer key: 1. The cinema and the museum. 2. The museum — a new exhibition is starting. 3. He offers to order/buy the tickets online (*pido los billetes*).

Pronunciation notes: this lesson's sounds

• ie and ue are single gliding syllables: *pienso* = "PYEHN-soh" (2 syllables), *puedo* = "PWEH-doh". Do not split them into two syllables.
• In digo, hago, pongo the g is a soft voiced sound, more like a gentle gargle between vowels than the hard English "g" of *go*.
• voy, doy, estoy, soy — the final y sounds like the Spanish vowel i; keep these one-syllable words short and crisp.

Common mistakes (wrong → right)

• ✗ *Yo penso* / *nosotros piensamos* → ✓ Yo pienso, nosotros pensamos — the change happens only *inside* the boot.
• ✗ *Yo sabo la respuesta* → ✓ Yo sé la respuesta — saber's yo form is sé.
• ✗ *Voy a voy mañana* → ✓ Voy mañana or Voy a viajar mañana — in *ir a + infinitive*, the second verb stays in the infinitive.
• ✗ Using *conocer* for facts: *Conozco la capital* → ✓ Sé la capital (facts = saber); conozco is for people and places: *Conozco a María; conozco Madrid.*

Exam Experience

Reading comprehension. Read and answer in English. *Todos los días, Marta se levanta a las seis. Piensa en su día mientras desayuna. Quiere terminar su proyecto hoy porque mañana va a viajar a Valencia. No puede trabajar por la noche: duerme mal cuando trabaja tarde. Por la tarde pide ayuda a su compañero Tomás, que entiende el problema. A las siete, ellos cierran la oficina y vuelven a casa.* 1. What does Marta think about while she has breakfast? (1 mark) 2. Why does she want to finish the project today? (1 mark) 3. Why can't she work at night, and who helps her in the afternoon? (2 marks) Answer key: 1. Her day (plans for the day). 2. Because tomorrow she is travelling to Valencia. 3. She sleeps badly when she works late; her colleague Tomás helps her.

Multiple choice. 1. Nosotros ___ al fútbol los sábados. a) juegamos b) jugamos c) juegan. Answer: b — nosotros is outside the boot, so no stem change. 2. Yo ___ la verdad. a) sabo b) se c) sé. Answer: c — saber's yo form is sé (written accent distinguishes it from *se*). 3. Ellos ___ a casa a las diez. a) vuelven b) volven c) vuelve. Answer: a — volver is o→ue: vuelven.

Guided writing task. Write 40–50 words about your plans for next weekend: use *ir a* + infinitive at least twice, one boot verb, and one yo-go verb. Model answer: *El sábado voy a visitar a mi familia. Quiero ver a mis abuelos y pienso llegar a las once. Mi hermano no puede venir porque trabaja. Por la tarde, salgo con amigos y jugamos al tenis. El domingo duermo hasta tarde.* Marking notes: content marks for at least three distinct activities; language marks for *ir a* + infinitive (not *ir a* + conjugated verb), the boot change correctly placed (quiero/pienso), and a correct yo form (salgo). Deduct where nosotros forms get a stem change.

Going further: two more irregular families

Two more patterns complete your irregular toolkit. First, verbs ending in -uir insert a y: construir (to build) — construyo, construyes, construye, construimos, construyen; incluir (to include), huir (to flee/run away) behave the same. Second, the -car / -gar / -zar verbs are regular in the present but will change spelling in the preterite (Lesson 7) and subjunctive (Lesson 10): *buscar* (to look for), *llegar* (to arrive), *empezar* (to begin). File them mentally now. And here is a treasure chest of high-frequency phrases built from this lesson's verbs:

One more distinction the examples hid: pedir (e→i) means to ask *for* something or order, while preguntar means to ask a *question*: Pido un café y pregunto el precio — I order a coffee and ask the price. And jugar takes a before sports: *jugar al fútbol, jugar al tenis*. Drill sentence that packs the lesson into one line: Siempre pido lo mismo, pero hoy quiero probar algo nuevo: ¿puedes recomendarme un plato? — I always order the same thing, but today I want to try something new: can you recommend a dish?

Workshop: the verb auction

Here is a game that fixes irregular verbs permanently. Take these twelve sentences and "bid" on the correct form — say the full sentence aloud before checking: 1. Yo (conocer) ___ a tu hermano. → conozco 2. Ellos (querer) ___ salir ya. → quieren 3. Nosotros (dormir) ___ ocho horas. → dormimos (outside the boot!) 4. Tú (decir) ___ la verdad. → dices 5. Ella (poder) ___ venir mañana. → puede 6. Yo (salir) ___ a las ocho. → salgo 7. Vosotros (pedir) ___ perdón. → pedís (vosotros keeps the e→i here: pedís — in fact -ir stem-changers *do* change in vosotros for e→i verbs; note this exception) 8. El café (costar) ___ tres euros. → cuesta 9. Yo no (saber) ___ su nombre. → sé 10. Ellos (jugar) ___ al baloncesto. → juegan 11. Nosotros (pensar) ___ en ti. → pensamos 12. ¿(venir) ___ tú a la fiesta? → vienes Sentence 7 hides a refinement: for e→i verbs (pedir, servir, vestir), the nosotros/vosotros forms *also* change in another tense — the preterite third person (*pidió*) — but in the present, vosotros *pedís* carries the i. And for o→ue -ir verbs like dormir, nosotros in the *subjunctive* (Lesson 10) becomes *durmamos* — a surprise the language keeps for later. For now, the auction's twelfth sentence is your model: any form, any person, one breath, no hesitation.