Lexicality effects in single-word naming in alphabetic Turkish orthography.

The cognitive processes involved in single-word naming of the transparent Turkish orthography were examined in a series of naming experiments on adult native speakers. In Experiment 1, a significant word frequency effect was observed when matched (i.e. on initial phoneme, letter length and number of syllables) high and low frequency words were presented for naming. However, no frequency effect was found in Experiment 2, when an equal number of matched nonword fillers were mixed with the target words. A null frequency effect was also found in Experiment 3 when experimental conditions consisted of mixed-blocks, i.e. high and low frequency were words presented in two separate blocks mixed with an equal number of matched nonwords. In Experiment 4, frequency was factorially manipulated with imageability (high vs. low) and level of skill (very skilled vs. skilled) which found significant main effects for word frequency and level of skill, and a significant 2-way interaction of skill by imageability and a significant 3-way interaction of skill by imageability by frequency. In Experiment 5, however, there was only a main effect for frequency when less skilled readers performed on the same words used in Experiment 4.
Collectively, these findings suggest that whilst a lexical route dominates in naming the transparent Turkish orthography, an explanation that the readers shut down the operation of this route in the presence of nonword fillers is not entertained. Instead, the results suggest that both routes operate in naming, with the inclusion of filler stimuli and their “perceived difficulty” having an impact in the time criterion for articulation. Moreover, there are indications that a semantic route is involved in naming Turkish only when level of skill is taken into account.
Implications of these findings for models of single-word naming and literacy assessment, and intervention are discussed.