Xtext is a well-known domain-specific language design framework and technology. It automatically generates a textual grammar for a language, given a meta-model specified in Ecore. These generated textual grammars are typically not user-friendly. Python-style languages are popular among developers for their usability and conciseness. We aim to propose a systematic approach to transform a DSL with a generated grammar into a Python-style DSL. To achieve this, we analyze the problems of grammars generated with Xtext, based on a lightweight architecture description language. In response to these problems, we propose a general semi-automated grammar adaptation approach. We apply the approach to two other DSLs to validate the generalization of the approach. We also discuss the limitations of this approach and prospects for the future.