Elaborate, ’to expand something in detail,’ originates with Latin. Elaboration is often used to explain or clarify – for example, in foreign language teaching.
Elaboration is presented as an alternative to easy-to-read text. Katriina Rapatti says in her article Text Interactivity as the Key to Understanding (available only in Finnish) that for a language learner an easy-to-read text can be verbally too narrow. If all abstract expressions and difficult structures are eliminated, the learner cannot expand his linguistic skills. Instead of removing all the difficult expressions, the text should provide explanation for them. This means in practice that the elaborated text often becomes longer than either the original or the easy-to-read version.
Elaboration uses the same methods by which native speakers facilitate the understanding of a foreign-language interlocutor. According to Rapatti, elaboration is the combination of two language forms: written language enriched with explanations used mainly in spoken language. The text becomes the reader’s understanding partner.
I think the difference between clarification and elaboration is more in perspective than in practical editing. In practice, easy-to-read texts often include examples and descriptive additions. However, retaining different levels of language, as elaboration stresses, is an important viewpoint.