Download MP3 upto Fifty thousand characters as same as fromtexttospeech

what I wanted to do is make another similar websites as fromtexttospeech.com with these few changes . This site is given 50000 characters download with ivona voice for free. Please take a look of this site for reference. Here is the details of my requirements are given below
It will be my websites features

Easily convert your text to MP3 save text for future listen
Download Audio files for free


Users page
Listen and stop button
Registration is required only for savings text
Every new registered users will able to save text can view from Thier own profile

Users only can view dashboard and savings text
For listen text can load in text area
MP3 downloads will automatically deleted after 24 hours
Here is the language and voice list are given below
Default language Us English
Default voice Alice
Default speed medium
Us English voice list Alice
Daisy
George
Jenna
John
British English list
Emma
Harry
French language list
Gabriel
Jade
Spanish language list
Isabella
Mateo
German language list
Michael
Nadine
Italian language list
Alessandra
Giovanni
Portuguese language list
Rodrigo
Russian language list
Valentina
Select speed
Slow
Medium
Fast
Very fast