Does speaking a different language affect inner speech? Does it matter what language we think in?

Yes, inner speech will then be conducted in this new language. Psychologists today think of memory and how we see the world as relying on how we describe things using words. If those words are different, it is possible that maybe our worldview will be different.

So speaking a different language can potentially influence how we see the world, which was first written about in psychology by Edward Sapir and Benjamin Lee Whorf. Whorf studied how speakers of Native American languages represent tragedy differently than English speakers and developed the hypothesis of “linguistic relativity” based on the ideas of his mentor, Sapir; this hypothesis suggests that language determines how we think. However, some researchers, like Steven Pinker, argue that there is no linguistic basis for how we see the world, and others have found inconclusive results in investigations on whether language affects perception. 

Several studies have looked into how different languages affect perception, with varying results.

For instance, Eleanor Rosch found that speakers of the Dani language in Papua New Guinea, which only has two words to describe color, performed similarly to English speakers in distinguishing between color shades. Similarly, some researchers have looked at geometry skills based on speakers of languages with fewer words for how things are shaped and where they are. The results of these tests found that generally, even though they do not have words to describe shape concepts, these speakers understand and process differences between shapes and where they are placed. The results of these two studies suggest that the language that the participant thinks in may not affect how they see the world (supporting Steven Pinker).

However, in another study, psychologist Lera Boroditsky examined how language affects our perception of time and motion. Boroditsky found that Mandarin speakers had an advantage when shown images of time moving vertically because time can be described in both vertical and horizontal metaphors (vertical: “above” and “below” in Mandarin), while English speakers were faster with horizontal images ("before" and "after"), as English speakers use horizontal metaphors to describe time. Also, in another experiment involving motion and how we describe it, English monolinguals (who have many words to describe motion, such as “trot” and “scamper”) performed better than speakers of Japanese and Spanish, who have fewer words to describe different kinds of motion, when comparing two scenes in which a ball is moving in different ways. Finally, some researchers have had people learn new words to describe colors that don't have words in English (different shades of blue), and found that learning the words helped these people react to differences in the colors more quickly. These results suggest that actually, the language might change how we see the world (supporting Sapir and Whorf). 

The famous book 1984 by George Orwell also plays with these themes -- the authoritarian government does not provide the people with a word for "revolution", in hopes that they will not even be able to understand the concept without a word for it (and thus won't rise up against their evil leaders).

Overall, some researchers believe that language can influence how we see the world, and investigations so far are inconclusive. Inner speech is conducted in the language of the thinker, but whether this language affects perception remains a subject of ongoing research and debate. 

See the images on the right for what the researchers used to test people (and images of some of the researchers) ->

Do people with accents still have accents when they think?

Yes! A study in 2019 found that American English speakers with Northern and Southern accents did, in fact, think in their regional accents (not a surprise, because why wouldn't they?  but still a cool tidbit!)

As for how the researchers figured it out, they tracked the eye movements of people with Northern and Southern accents when reading a rhyming poem. The participants knew the poem was supposed to rhyme, so if they read the poem and it did not rhyme in their regional accent, their eye movements got disrupted. The disruption means that they were reading it in their regional accent! 

For an example, you can test yourself on the What is inner speech?  page -- check out the children's book next to the explanation of phonological judgement experiments. Did the words rhyme for you or not?