Human thought, for the majority, is not simply the individual outcome of our evolved neural architecture, but also the result of our borrowing of the immense symbolic and intellectual resources available in language. What would human thought be like without language? . . .
My own feeling, and I have not worked with a population that has a non-Western sense of time, is that it’s likely a softer form of the Whorfian argument, that language and culture affect the perceptual qualities of different sensory channels to varying degrees (perhaps more in some phenomenal qualities than in others) is the most defensible (and arguably, this is what Whorf was arguing all along). Time, for example, may be difficult to perceive in certain ways if you are not culturally trained to habitually conducting yourself in relation to time appropriately: certainly, there is deep cultural difference in the degree to which people orient themselves by the clock, and varying emphases that societies place on recurrence or irreversibility of time. This isn’t to say that language is a perceptual world, but rather than languages can induce certain perceptual biases that may be more or less difficult to overcome. But what about those without language? . . .
So can people have thought without words? Well, the evidence-based answer would seem to be, yes, but it’s not the same sort of thought. Some things appear to be easier to ‘get’ without language (such as imitation of action), other things appear to be a kind of ‘all-at-once’ intuition (such as suddenly realizing all things have names), and other ideas are difficult without language being deeply enmeshed with cognitive development over long periods of time (like an English-based understanding of time as quantitative and spatialized). In other words, language is not simply an either/or proposition, but part of a cognitive developmental niche that shapes both our abilities and (unperceived) disabilities relative to the fully cognitively matured language-less individual.