Bilinguals may choose to speak a language either at their own will or in response to an external demand, but the underlying neural mechanisms in the two contexts is poorly understood. In the present study, Chinese–English bilinguals named pairs of pictures in three conditions: during forced-switch, the naming language altered between pictures 1 and 2. During non-switch, the naming language used was the same. During free-naming, either the same or different languages were used at participants' own will. While behavioural switching costs were observed during free-naming and forced-switching, neuroimaging results showed that forced language selection (i.e., forced-switch and non-switch) is associated with left-lateralized frontal activations, which have been implicated in inhibitory control. Free language selection (i.e., free-naming), however, was associated with fronto-parietal activations, which have been implicated in self-initiated behaviours. These findings offer new insights into the neural differentiation of language control in forced and free language selection contexts.

中文翻译：

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神经影像学证据将双语语音生成过程中的强制语言选择与自由语言选择分开

双语者可能会根据自己的意愿或响应外部需求选择说一种语言，但这两种情况下的潜在神经机制人们知之甚少。在本研究中，汉英双语者在三种情况下对图片对进行命名：在强制切换期间，命名语言在图片 1 和 2 之间变化。在非切换期间，使用的命名语言相同。在自由命名过程中，参与者可以根据自己的意愿使用相同或不同的语言。虽然在自由命名和强制切换期间观察到行为切换成本，但神经影像学结果表明，强制语言选择（即强制切换和非切换）与左外侧额叶激活相关，而左外侧额叶激活与抑制控制有关。然而，自由语言选择（即自由命名）与额顶叶激活有关，而额顶叶激活与自我发起的行为有关。这些发现为强制和自由语言选择环境中语言控制的神经分化提供了新的见解。