A century of research has provided evidence of limited size sound symbolism in English, i.e., certain vowels are non-arbitrarily associated with words denoting large versus small referents. In the present study, we investigated more extensive statistical regularities between surface form properties of English words and ratings of their semantic size, i.e., form typicality, and its impact on language and memory processing. Our findings provide the first evidence of significant word form typicality for semantic size. In four empirical studies using behavioural megastudy datasets of performance on written and auditory lexical decision, reading aloud and recognition memory tasks, we show that form typicality for size is a stronger and more consistent predictor of lexical access during word comprehension and production than semantic size, and plays a significant role in verbal memory. The empirical results demonstrate that statistical information about form-size mappings is accessed automatically during language and verbal memory processing, unlike semantic size that is largely dependent on task context.