Mark My Words: High Frequency Marker Words Impact Early Stages of Language Learning

High frequency words have been suggested to benefit both speech segmentation and grammatical categorisation of the words around them. Despite utilising similar information, these tasks are usually investigated separately in studies examining learning. We determined whether including high frequency words in continuous speech could support categorisation when words are being segmented for the first time. We familiarised learners with continuous artificial speech comprising repetitions of target words, which were preceded by high- frequency marker words. Crucially, marker words distinguished targets into two distributionally-defined categories. We measured learning with segmentation and categorisation tests, and compared performance against a control group that heard the artificial speech without these marker words (i.e., just the targets, with no cues for categorisation). Participants segmented the target words from speech in both conditions, but critically when the marker words were present, they influenced acquisition of word-referent mappings in a subsequent transfer task, with participants demonstrating better early learning for mappings that were consistent (rather than inconsistent) with the distributional categories. We propose that high-frequency words may assist early grammatical categorisation, while speech segmentation is still being learned.