Crochet charts are becoming more common these days. As crochet chart symbols are really cool if you do not like to read patterns. Sometimes they are included in as an addition to a written pattern or in place of one. I find that using chart symbols are really needed especially when a pattern is in another language. It makes the translation easier.
You can check out the crochet abbreviations HERE
When working a pattern make sure to always look at the pattern key for any additional chart symbols the designer may use for that pattern.
Source: Craft Yarn Council’s www.YarnStandards.com