This article presents an analysis of vowels in the goat set and /r/ in the Collection of Nineteenth-century Grammars (CNG) (cf. Anderwald 2016). My central questions concern the extent to which grammarians provide evidence for early diphthongisation in goat words and for changes in the distribution of /r/ variants in nineteenth-century prestige accents. I furthermore evaluate how far grammars are suitable as a source for researching historical sound changes. I show that monophthongs are the most frequently proposed variants for goat and are often referred to as ‘improper diphthongs’. Some diphthongal descriptions exist for words in open syllables, before /l/ and before plosives in words like know, soul and boat respectively. Concerning the distribution of /r/, I show that most grammars continued to propose two sounds, which were almost exclusively described as ‘rough’ or ‘trilled’, and ‘smooth’ or ‘soft’. However, some grammarians also argued for /r/ having only one sound in all positions and complete post-vocalic /r/ absence. Overall, the grammars in the CNG display a considerable amount of what I assume to be copying from scholars such as Walker (1791) and Murray (1795). Thus, I argue that great care is required when attempting to infer phonological changes from nineteenth-century grammars.