Nasal describes anything related to your nose. When you have a cold and sound funny while talking, that's a nasal voice: air is flowing through your nose instead of just your mouth, creating that stuffed-up, honking quality. Say “banana” while pinching your nose shut, and you'll hear how different it sounds when the nasal passage is blocked.

Doctors use nasal to describe the anatomy and medical issues connected to the nose. A nasal spray goes up your nostrils to help with congestion. Nasal passages are the airways inside your nose that warm and filter the air you breathe.

In phonetics (the study of speech sounds), nasal consonants are sounds like “m,” “n,” and “ng” that you make by letting air flow through your nose. Try humming: you're making a nasal sound. Now hold your nose and try to hum. You can't! That's because humming requires air to flow through your nasal passages.

Some people naturally speak in a more nasal way than others, which is just part of how their voice sounds. But if someone suddenly develops a nasal voice when they're sick, it's because swollen tissues are blocking normal airflow.