When kids start learning Spanish, there are a few phrases they usually learn right away. Hello. Goodbye. My name is…
Those are all important, but there is one phrase that helps children feel confident from day one and continues to help them even as they become advanced speakers.
That phrase is “I don’t know.”
Knowing how to say “I don’t know” in Spanish teaches kids that it is okay not to have all the answers. It gives them a way to participate in class without feeling embarrassed and encourages them to keep speaking instead of shutting down.
This phrase is also useful far beyond Spanish class. Kids use it in everyday life when they do not know how to solve a math problem, follow instructions, or figure something out. Learning it early builds confidence and communication skills.
Below are 10 common ways kids can say “I don’t know” in Spanish, from simple and polite to playful and informal.
The Most Common Ways to Say “I Don’t Know” in Spanish
No sé
This is the most common and useful way to say “I don’t know” in Spanish. Kids, teens, and adults use it every day. You may also hear “No lo sé,” which means the same thing and sounds just as natural.
Example:
No sé las respuestas del examen.
I don’t know the answers to the exam.
Ni idea
This phrase means “no idea.” It is used when someone truly does not know something at all. It is casual and very common among kids and adults.
Example:
¿Sabes qué dejó la maestra de tarea?
Do you know what homework the teacher gave?
¡Ni idea, no presté atención!
No idea, I was not paying attention.
No tengo idea
This means “I have no idea” and is very similar to “ni idea,” just a bit longer. You may also hear both phrases together as “No tengo ni idea.”
Example:
No tengo idea de cómo armar este set de Lego.
I have no idea how to build this Lego set.
No tengo la más mínima idea
This phrase adds emphasis and means “I don’t have the slightest idea.” Other similar versions include “No tengo la menor idea” or “No tengo la más remota idea.”
Example:
No tengo la más mínima idea de qué botana llevar al convivio escolar.
I don’t have the slightest idea which snack to bring to the school party.
Casual and Playful Ways Kids Often Hear
Quién sabe
This means “who knows.” It can be a real question, but it is often used as an answer when someone does not know. Kids usually say it with a shrug.
Example:
Niños, ¿quién rompió el vaso?
Kids, who broke the glass?
¡Quién sabe!
Who knows.
Sepa la bola
This is a fun, informal expression that also means “who knows.” It is very casual and should not be used with teachers or in serious situations. Tone matters a lot with this phrase.
Example:
¿Por qué las paredes están rayadas con crayones?
Why are the walls covered in crayon marks?
¡Sepa la bola!
Who knows.
Sepa
This is a shortened slang version commonly used in Mexico. Kids like it because it is quick and playful, but it is still informal.
Example:
¿Qué le pasó a Miguel?
What happened to Miguel?
¡Sepa!
I don’t know.
Phrases Kids Should Recognize but Use Carefully
Yo qué sé
This means “what do I know.” It can sound rude depending on tone, so it is not something kids should use often. However, it is helpful for them to recognize it when they hear native speakers use it.
Example:
¿Qué le pasó a mi muñeca? No la encuentro.
What happened to my doll? I can’t find it.
¡Yo qué sé!
What do I know.
No sabría decirte
This phrase is more formal and usually used by adults. It means “I wouldn’t know” or “I couldn’t tell you.” Kids might hear it and want to try it when playing or pretending to sound serious.
Example:
No sabría decirte quién ganó el juego.
I couldn’t tell you who won the game.
Lo desconozco
This is another formal way to say “I don’t know.” Children rarely use it, but it is common among adults.
Example:
Desconozco en qué trabaja mi tío.
I don’t know what my uncle does for work.
Learning Spanish Is Easier in a Supportive Environment
If your child is learning Spanish, they need more than vocabulary. They need a space where it is okay to say “I don’t know,” make mistakes, and keep trying.
That is exactly what TruFluency Kids provides.
Our live online Spanish immersion classes are taught by native teachers and designed specifically for kids. Classes are active, engaging, and fun, using singing, games, storytelling, movement, and creative activities. English is used very little so children naturally acquire Spanish the same way they learned their first language.
With the Bellieu Method, students speak Spanish in every single class, regardless of their starting level. Beginners are welcome, as well as kids who already have some exposure to Spanish.
Most importantly, TruFluency Kids is a safe place to learn. Kids do not need to know everything. Saying “no sé” is part of the process.
Give your child a confident start in Spanish. Drop into a class and join a parent Q&A afterwards to get all your questions answered.
