Update README.md (#48)

README.md

@@ -5,7 +5,7 @@
 [![Documentation](https://img.shields.io/badge/docs-latest-green)](https://xgrammar.mlc.ai/docs/)
 [![License](https://img.shields.io/badge/license-apache_2-blue)](https://github.com/mlc-ai/xgrammar/blob/main/LICENSE)
 
-**Fast, Flexible and Portable Structured Generation**
+**Efficient, Flexible and Portable Structured Generation**
 
 
 [Get Started](#get-started) | [Documentation](https://xgrammar.mlc.ai/docs/) <!-- TODO: | [Blogpost](https://blog.mlc.ai/TODO) -->
@@ -14,7 +14,7 @@
 
 ## Overview
 
-XGrammar an open-source library for fast, flexible, and portable structured generation.
+XGrammar an open-source library for efficient, flexible, and portable structured generation.
 It supports general context-free grammar to enable a broad range of structures while bringing careful system optimizations to enable fast executions.
 XGrammar features a minimal and portable C++ backend that can be easily integrated into multiple environments and frameworks,
 and is co-designed with the LLM inference engine and enables zero-overhead structured generation in LLM inference.