Not neccessarily. By default the autocomplete uses google suggestions, so it's hard to predict what words will come out, it's up to google in that case.
If different sources are chosen (like post titles etc..), then the script checks for similar titles for the entered words, and one character cut off from the start and the end of the entered words. Anything more complicated, like recognizing words and meanings would require a 3rd party dedicated service, like google CSE or similar. It still would be extremely hard to configure for exact needs.Best,
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