The present study investigated neural correlates of implicit phonotactic processing in 18-month-old children that just reached an important step in language development: the vocabulary spurt. Pseudowords, either phonotactically legal or illegal with respect to their native language, were acoustically presented to monolingually German raised infants. Neural activity was simultaneously assessed by means of electroencephalography (EEG) and functional near-infrared spectroscopy (fNIRS). The former method excellently tracks fast processing mechanisms, whereas the latter reveals brain areas recruited. Results of the present study indicate that 18-month-olds recognize the linguistic properties of their native language based on phonotactics. This manifested in an increased N400 for legal compared to illegal pseudowords in the EEG conforming to adult-like mechanisms. Unfortunately, fNIRS findings did not support this discrimination ability. Possible methodological and brain maturational reasons might explain this null finding. This study provides evidence for the advantage of a multi-methodological approach in order to get a clear picture on neural language development.

本研究调查了18个月大的孩子中隐性音韵处理的神经相关性，这些孩子刚刚达到了语言发展的重要步骤：词汇量突增。假单词在语音上在法律上是合法的或在其母语上是非法的，已被以声学方式呈现给德语的抚养婴儿。同时通过脑电图（EEG）和功能性近红外光谱（fNIRS）评估神经活动。前一种方法很好地跟踪了快速处理机制，而后一种方法则揭示了招募的大脑区域。本研究的结果表明，18个月大的孩子基于语音疗法能够识别其母语的语言特性。与符合成人机制的EEG中的非法伪字相比，法律的N400增加了。不幸的是，fNIRS的发现不支持这种歧视能力。可能的方法论和大脑成熟的原因可能解释了这一无效发现。这项研究为多方法论方法的优势提供了证据，以便清晰地了解神经语言的发展。