English doesn't have the exact same nasal vowel sound as Portuguese. Although not an exact match, the "ang" part of the word "tang" can provide a helpful starting point and a close approximation of the nasalized [ã] sound in Portuguese. See the section "NOTES" below for more information.
Examples:
The IPA sound /ã/ is a nasalized open front unrounded vowel. This means that it is produced by raising the tongue to the front of the mouth, but not rounding the lips. The sound is also nasalized, which means that the airstream is allowed to escape through the nose, giving the sound a "nasal" quality. It's important to note that the mouth remains open.
The /ã/ sound is often described as a "long a" sound, because it is the sound that is made when you say the word "aunt". It is also sometimes called a "nasal vowel", because it is produced with a nasal sound.
NOTES
As mentioned at the start of this page, when it comes to approximating this sound in English, the "ang" part of the word "tang" can provide a helpful starting point.
When you practice with the word "tang" or any Portuguese word that has a nasal vowel sound, it's important to keep your mouth open until the end of the word and let the air pass through your nose.
In the beginning, I recommend that you purposely push out more air through your nose at the end of the 'ng' part of the word. This will help you get a better feel for the nasalized sound.
As you progress, you can gradually reduce the amount of air you release through your nose. This step-by-step approach will allow you to refine your pronunciation and make it more natural over time. Keep practicing and remember to pay attention to how the airflow feels in your mouth and nose.
Practice will help you become more familiar with the nasalized vowel sound and improve your pronunciation. Remember to pay attention to the way your mouth and nose feel when producing these sounds, as nasalization involves airflow through the nasal passage.
Additionally, listening to native speakers of Brazilian Portuguese and imitating their pronunciation can also be beneficial in developing a better understanding and ear for the nasalized vowel sound.