Multiple Phonological Access Pathways and their Creation: The case of Number Words

Accumulating evidence shows that the phonological production of words does not follow a single pathway, as was assumed in the past. Rather, some words are produced via dedicated production pathways. Previous studies showed such pathway separation for words from different categories (e.g., number versus non-number words) or with different meanings (number words with numerical versus non-numerical meaning, e.g., ‘Nine West’). Here, we show that the separation of phonological production pathways is even greater than that: even the same word with the same meaning can follow different phonological production pathways, depending on the context in which the word is produced. We report HLI, a woman with aphasia. She erred in 5 number-production tasks, all with phonological output but with different input modalities: digits, written number words, dice patterns, encyclopedic questions, and approximate quantities. We conclude she had impaired phonological production of number words. Critically, she performed relatively well in 3 other phonological number production tasks: oral calculation, counting, and repetition. This dissociation indicates multiple phonological production pathways for verbal numbers. We propose that HLI has a deficit in a default phonological production pathway, which serves most number-production tasks. At the same time, other, dedicated pathways of phonological number production, which are recruited uniquely by the calculation, counting, and repetition tasks, are spared. Finally, we propose a concrete model that explains when and how the dedicated, task-specific phonological-access pathways are created, and we show that HLI’s performance satisfies a central prediction of this model.