Students commonly find the language of chemistry challenging and a barrier to developing understanding. This study investigated developments in chemical language understanding by a group of non-traditional students over the duration of a one year pre-undergraduate (Foundation) course at a UK university. The chemistry course was designed to include a range of literacy based strategies to promote understanding including: word games, corpus linguistics, word roots and origins, and reading comprehension. Understanding of chemical language was assessed with a chemical language assessment (CLA) that was administered three times during the year. The CLA assessed understanding of scientific affixes, symbolic language, non-technical words, technical words, fundamental words and topic-specific vocabulary. Results indicate that chemical language understanding improved over the duration of the study with moderate to large effect sizes. Students who scored low in the initial CLA (below 40%) improved but their scores remained lower than the rest of the students at the end of the year. The topic-specific and technical sections scored low for all students at the start of the year and remained the lowest at the end of the year. Examples of symbolic and non-technical language remained problematic for some students at the end of the year. There was a correlation (r = 0.53) between initial CLA score and final exam outcomes although some students with low initial CLA scores did perform well in the final exam. These findings are discussed in relation to the role of literacy based strategies in chemistry teaching.