How to split natural language script into segments?
I haven't seen anything like this before but it seems quite feasible. You need an ontology to separate the main concept into its subconcepts, then you need a classifier to distinguish between your broader categories; description, methodology, classifier, application, and example. That is, I would manually label some transcripts at the paragraph level. If you don't have paragraph-segmented text, smooth the classification probability over the sentences so they share the same label. Or use a paragraph segmentation model as in Automatic Paragraph Segmentation with Lexical and Prosodic Features.

The classifier could be a CRF or an RNN. The modern way to induce the ontology would be through word embeddings; cf. e.g, Learning Semantic Hierarchies via Word Embeddings. Formerly I would have recommended a hierarchical topic model, such as hLDA; cf. e.g, Non-Parametric Estimation of Topic Hierarchies from Texts with Hierarchical Dirichlet Processes or Unsupervised Terminological Ontology Learning based on Hierarchical Topic Modeling

Welcome to the site and good luck!