「心理的演講」(inner speech)也被一些人視為是一個「語言決定論」(linguistic determinism)的版本。在這樣的觀點中，自己內心的聲音就被視為是自己思考的過程。自然語言在這樣的觀點中，比較像是額外的心理表徵。嬰兒會有思考的語言；而成人在思考的語言之外，額外有一個自然語言(可能是英語、華語會任何語言)。
當我們在組織一個文章或者想像要跟某個人說什麼話的時候，就是需要依靠「心理演講」的認知任務。但是也有人認為，「心理演講」在因果推論(causal reasoning)、社會認知等方面扮演了更積極的角色(Carruthers, 1998) 。例如思考「自己若不去參加派對，某個人會怎麼反應的時候。」當沒有自然語言的的支援時「How will Jane react if I don」t go to her party?」，可能我們就無法思考更多情境。
把MM豆外觀的鐵盒子裡放幾枝鉛筆，然後搖一搖讓它出聲音，接著問小朋友，裡面裝什麼。小朋友可能會猜是MM豆，打開盒子之後讓小朋友看到鉛筆。接著問他沒看到盒子裡面東西的小朋友，會回答盒子裡有什麼？四歲之後的小朋友就會回答MM豆，但是更小的小朋友就會說是鉛筆。這是一個推測他人心理想法的實驗例子(false-belief task)(Wimmer & Perner, 1983; Perner,Leekam & Wimmer, 1987) 。有一些人認為這是任務本身的認知要求較高，所以小孩子無法完成(Leslie, 1994) ；有一些人認為，這個情境還沒能讓小孩子編碼到(encode)自然語言裡頭(De Villiers & De Villiers, 1997)。
有一些成年之後失語症(aphasics)的患者，存在語言和思考解離的徵狀。這些人並不是智障，他們有正常的行為，雖不會手語也能畫畫、比劃，他們就像是被剝奪了溝通的能力。他們在語言能力上的缺陷，常常必需透過其它溝通管道來彌補。有報告認為，由於心理演講的機制出了問題，缺少了來自頭腦深層的聲音，有一些失語症患者的主體性(subjective experience)變得更差(Goodglass,Denes & Calderon, 1974) 。Rosemary把類似MM豆的實驗讓失語症患者進行，這些患者在理解或產出句子很有問題，頂多就是一些分離的詞語，但是所有人都可以完成任務。我們很難說「語言」就和「思考」沒有關聯，畢竟這些都是曾經擁有語言的患者。但是，我們可以說進行因果或意向推論的時候，似乎不需要使用自然語言。
也有研究從失語症的患者身上，論述了精確數字推理(當成是語言(arguably the product of language))和約略的數字估算(arguably the product of the accumulator mechanism)的解離(Dehaene, 2011) 。但尚沒有證據顯示是否是因為缺少數字的詞語，而無法進行數字運算。
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