12. A computer program product having a set of computer readable instructions, which when loaded into a memory of a computer system and executed by one or more processors of the computer system, cause the computer system to perform text generation based on an audio speech signal with the steps of: receiving 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 of the speed parameter and the at least one acoustic parameter associated with the respective grapheme.
12. A computer program product having a set of computer readable instructions, which when loaded into a memory of a computer system and executed by one or more processors of the computer system, cause the computer system to perform text generation based on an audio speech signal with the steps of: receiving 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 of the speed parameter and the at least one acoustic parameter associated with the respective grapheme. 13. The computer program product of claim 12 , wherein determining the at least one acoustic parameter further comprises normalizing a plurality of acoustic parameters by applying respective acoustic normalization functions; wherein determining the speed parameter further comprises normalizing the speed parameter by applying a speed normalization function; and wherein generating the character shape further comprises determining visual shaping parameters based on the normalized speed and acoustic parameters.