An attempt was made to compare and contrast observations and assessments made by neurosurgeons, psychologists, and speech therapists, with special reference to speech and language correlates of the ventrolateral thalamic nucleus. While findings must be considered preliminary and in need of corroboration and refinement, the following conclusions are offered: 1.(1) Alterations of fluency, presence of hesitations, and blocking in language may occur immediately after a left ventrolateral thalamic lesion in right-handed patients. These changes cannot be distinguished from dysphasia frequently described following left-sided cortical lesions. Such alterations can be definitely associated with a thalamic rather than a cortical lesion. When these alterations occur in patients operated upon unilaterally, language functions return to the preoperative level within several weeks after surgery.2.(2) Alterations in complex language may also occur after the placement of unilateral right hemisphere thalamic lesions in right-handed patients. Such changes are ordinarily detected by tests of verbal crystalized functions involving permutations of symbols and relations among signs and symbols, rather than fluency. Findings based on such tests revealed a lack of significant qualitative differences between left and right thalamic lesions in this area, although quantitative differences are present.3.(3) A second-sided thalamic lesion may lead to a speech impairment in the nature of dysartheia. This is not a function of the laterality of “second-side” surgery. Changes in ventrolateral thalamo-cortical connections and their effects upon cortical outflows might be related to these defects.4.(4) Overall thalamic-cortical-thalamic circuits seem related to the language defects observed. It is proposed that alterations in linguistic fluency and flexibility following thalamic lesions can be attributed in part to a disturbance between specific and non-specific systems at a thalamic level. Such lesions may alter linguistic patterns by interfering with the activating aspects necessary to this function. At a thalamic level, greater activation may be required for adequate processing and elaboration of information. The fact that neural activating systems are essentially bilateral in nature may account for the fact that language functions seem to be more independent of lesion laterality after thalamic than cortical involvement.