To do a girl’s voice you will have to raise the back of your tongue and lower your soft palate to make your mouth smaller. Then raise Adam’s apple and increase the pitch. Finally, choose a particular female character from a movie or TV show and practice doing its impressions.
Raise the back of your tongue
To do a girl’s voice you’ll have to try to make your mouth smaller. To do so, try to raise the back of your tongue towards the roof of your mouth.
It will limit the space between the roof of your mouth and tongue. Also, it will naturally put your tongue in the right position for a girl’s voice.
You can try creating an “nnnn” sound to better understand how to raise the back of your tongue. By spelling the ‘n’ letter we naturally raise the back of our tongues. So you can better grasp a feel of how your tongue should be positioned when articulating an ‘n’ letter.
Lower soft palate
The soft palate is the upper part of the inside of your mouth. By lowering your soft palate you’ll again limit the space you use while speaking.
This will also focus more resonance on the front part of your face adding some nasal qualities to your voice which is more common for girls.
Raise Adam’s apple
Place a hand onto your Adam’s apple so you can track its movements. You need to raise your Adam’s apple to achieve a more feminine voice.
You can raise the Adam’s apple by lowering the tip of your tongue. This in turn will also help to raise the back of your tongue, which will all help to achieve a more feminine voice.
Practice lowering and raising your Adam’s apple, to make it easier to switch into a girl’s voice with ease.
Increase the pitch
Female voice has a higher pitch compared to men’s voice. Therefore, to sound more like a girl, you’ll be required to raise a pitch.
It doesn’t have to be crazy high, but just a tad bit higher than usual. You can read this article on how to achieve a higher voice.
Generally, to achieve a higher, more girly voice you’ll need to focus on speaking more from your face mask, use more nasal cavities and relax your upper body.
Try to copy a character from a movie or a show
Pick up a female character from a movie or TV show. Usually, characters with strong speech manners are easier to copy. While natural voices are much more nuanced, subtle and hard to do an impression of.
So, pick up a character with a strong personality and try to imitate its speech manner, vocal expressions, particular letters they emphasize, tempo, accent and so on, the more the better.
Watch the chosen character and try to catch small details that might help to do a better impression of it. If you want to read more about how to do voice impressions, this article will help a lot.
If you can copy your chosen female character’s body movements and facial expressions this will help to achieve a character voice much easier as your body will be more in sync with the voice.
Sound energetic and playful
Generally, most girls sound more energetic and playful than guys. Girls change the pitch and tempo much more often and usually talk more.
So, practice varying your pitch, tempo and speak a bit faster and more enthusiastically to sound like a girl.
Obviously, each character may have different speech patterns, but in general, these guidelines should fit most girl voices.
Edit your audio
If you’re not performing live, you can also edit your audio. Especially, it’s easy to change the pitch of your voice.
To do so, use change pitch or pitch correction effects in any DAW. Audacity is free, so you might as well use it.
Add a few semitones and your voice should start sounding much more like a girl’s.
You can also look into some mixers, that have EQ. If you plan to speak into the microphone online, then a mixer will help to raise the pitch a bit to sound more like a girl while speaking live.