The task of isolating 2 or more speakers is called speaker diarization,
here a list of softwares and useful resources.
Once you have the 2 or more audio files containing the individual voices, you could run some speech-to-text network that also outputs time information.
You would need to perform some kind of speech-to-text to get the audio transcription with the corresponding synchronization wrt the audio. Then search in the transcription.
You could use DSAlign by mozilla
Google has an API you can use. https://cloud.google.com/translate/. Their API can translate audio to text. They also have an API for converting speech to text. The language detection feature should let you detect the language in the resulting text. They have client libraries for the most popular programming languages.