A2, B1 3 hoursVerbs: Basics & Forms

Must and Have To: Complete Guide for Spanish Speakers

Medium A2B1

Internal vs external obligation. Both translate to 'deber/tener que', but MUST suggests personal necessity while HAVE TO suggests external rules.

Last Updated: January 15, 2026 | Reviewed by: María González

🎯 Why This Matters

To express obligation and necessity accurately.

Learning Outcome

Nuanced expression of different types of obligation.

🇪🇸 The Challenge

Internal vs external obligation. Both translate to 'deber/tener que', but MUST suggests personal necessity while HAVE TO suggests external rules.

🇲🇽🇨🇴🇦🇷 Mustn't confusion

Problem: Spanish 'no tengo que' = don't have to, but learners think mustn't

Watch out: Saying 'I mustn't work tomorrow' (meaning I'm not required) - wrong!

✅ Fix: MUSTN'T = forbidden. DON'T HAVE TO = not required. Different meanings!

🧠 Mental Note: mustn't = prohibited ❌ / don't have to = your choice ✓

❌ 'I mustn't go' (forbidden) vs ✅ 'I don't have to go' (not necessary)

🇪🇸 Same distinction needed

Problem: Spanish 'no debes' can be advice or prohibition

Watch out: MUSTN'T is always prohibition, never just advice

✅ Fix: For advice, use 'shouldn't'. For prohibition, use 'mustn't'.

'No deberías fumar' = You shouldn't smoke (advice). 'No debes fumar aquí' = You mustn't smoke here (prohibition).

🧠 Visual Explanation (The Mental Fix)

Internal Boss vs External Boss

Who's making you do it? MUST = Your internal boss 🧠 - 'I must call my mom' (I feel I should) - 'I must stop smoking' (personal conviction) - Source: YOU decided HAVE TO = External boss 👔 - 'I have to wear a uniform' (company rule) - 'I have to pay taxes' (law says so) - Source: Rules, laws, other people Negative = VERY different! - MUSTN'T = forbidden ❌ (you're not allowed) - DON'T HAVE TO = optional ✓ (no obligation) 'You mustn't smoke here' = prohibited! 'You don't have to tip' = your choice (not required)

MUST = I want to/feel I should. HAVE TO = external force. MUSTN'T = forbidden. DON'T HAVE TO = free choice.

🗣️ Pronunciation Guide

How Spanish speakers should pronounce this structure:

Have to pronunciation

Spanish Habit: Pronouncing 'have to' as two clear words

English Reality: 'Have to' sounds like 'hafta' /ˈhæftə/

Examples:

  • have to → /ˈhæftə/ (hafta)
  • has to → /ˈhæstə/ (hasta)
  • had to → /ˈhædtə/ (hadta)

Practice: Say 'hafta', 'hasta', 'hadta' for natural speech

📖 How It Works

Scenario analysis. Identifying source of obligation.
Learning Strategy

Teacher Recommendation: Self-study friendly

Time Investment: 3 hours

🔑 Signal Words (Memory Anchors)

These words/phrases appear with this structure:

English Spanish Example
must debo (convicción) I must exercise more / Debo ejercitarme más
have to tengo que (obligación) I have to work tomorrow / Tengo que trabajar mañana
mustn't no debes (prohibición) You mustn't tell anyone / No debes decirle a nadie
don't have to no tienes que (opcional) You don't have to wait / No tienes que esperar

💬 Real Examples

Let's see this structure in action with correct vs incorrect usage:

Example 1: Internal obligation

CORRECT: "I must lose weight. (personal decision)"

🇪🇸 Translation: "Debo bajar de peso."

COMMON MISTAKE: "Confusing with external obligation"

Why wrong? MUST shows personal conviction, from your own belief

🇲🇽 LatAm Trap: Both 'debo' and 'tengo que' translate similarly, but English distinguishes source

Example 2: External obligation

CORRECT: "I have to wear a helmet. (it's the law)"

🇪🇸 Translation: "Tengo que usar casco."

COMMON MISTAKE: "I must wear a helmet (sounds like personal choice)"

Why wrong? HAVE TO is better for rules and laws imposed by others

External rules, regulations, laws = HAVE TO

Example 3: Mustn't vs Don't have to

CORRECT: "You mustn't smoke here. / You don't have to tip."

🇪🇸 Translation: "No debes fumar aquí. / No tienes que dar propina."

COMMON MISTAKE: "Confusing mustn't and don't have to"

Why wrong? MUSTN'T = prohibited (forbidden!). DON'T HAVE TO = optional (no obligation)

🇲🇽 LatAm Trap: HUGE difference! 'No debes' ≈ mustn't (forbidden). 'No tienes que' ≈ don't have to (optional).
Mustn't = it's forbidden. Don't have to = it's not necessary

✏️ Practice Exercises

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