1. A computer-implemented method for text generation based on an audio speech signal executed by one or more processors of a computer system, the method comprising: receiving, by the computer system, the audio speech signal; extracting acoustic feature values of the audio speech signal at a predefined sampling frequency; mapping written words of a transcription of the audio speech signal to units of corresponding pronunciation objects; segmenting the audio speech signal including mapping the units of corresponding pronunciation objects to the received audio speech signal to determine a beginning time and an end time of the mapped units; aligning one or more units of the corresponding pronunciation objects to one or more graphemes based on a unit-grapheme mapping; determining a speed parameter for each aligned grapheme by using the beginning time and the end time of the corresponding aligned one or more of the units of the corresponding pronunciation objects; determining at least one acoustic parameter for each aligned grapheme including averaging the extracted acoustic feature values according to the beginning time and the end time of the corresponding aligned one or more units of the corresponding pronunciation objects; and generating, for each character of the aligned graphemes, a character shape representative of the speed parameter, a character shape representative of the at least one acoustic parameter associated with the respective grapheme, or a character shape representative the speed parameter and the at least one acoustic parameter associated with the respective grapheme.