All intelligent beings have communication.
All human communities have symbolic language. It can be signed or spoken, but it is a formal language.
Language and higher cognition go together. In general, they use overlapping and closely aligned parts of the brain.
Interestingly, some researchers make a case for formal language not being required.
Is thought possible without language? Individuals with global aphasia,
who have almost no ability to understand or produce language, provide
a powerful opportunity to find out. Astonishingly, despite their
near-total loss of language, these individuals are nonetheless able to
add and subtract, solve logic problems, think about another person’s
thoughts, appreciate music, and successfully navigate their
environments. Further, neuroimaging studies show that healthy adults
strongly engage the brain’s language areas when they understand a
sentence, but not when they perform other nonlinguistic tasks like
arithmetic, storing information in working memory, inhibiting
prepotent responses, or listening to music. Taken together, these two
complementary lines of evidence provide a clear answer to the classic
question: many aspects of thought engage distinct brain regions from,
and do not depend on, language. (ref)
I'm skeptical of the authors' conclusions. After all, these are people who can't use symbolic language, not people who belong to a culture that doesn't use it. And they are individuals who used to use language in a normal human way until their brain injury.
Thought is certainly possible without language. My skepticism is that I don't believe intelligent nondisabled humans wouldn't spontaneously create language if they didn't already have one.
Look at communities where deaf children are not exposed to sign language and only get so-so training in the spoken language (even great training won't make you a native user if you're unable to hear it). When these children get to spend time with other deaf children (or adults), they spontaneously create sign language.
One time this happened was in Nicaragua in the 1980's. Children with special needs stayed at home until after the 1979 revolution that brought universal education. But the schools for the deaf didn't teach sign, they taught lip reading. The kids, however, used their free time together and a language sprang up (they had some influence from others but the language is completely original).
There are plenty of studies where children had no or limited or arrested language input who still latched on to language as soon as they had the chance. It's part of human nature to use symbolic references.
So, yes, you can have thought without language, but no one with an option to choose to go without language does so.
If the only part of this you are asking about is the actual speech, then, yes of course, many people do not hear speech and many more do not use it. Formal symbolic language does not require speech or even sound.