Why split it into arrays first?
It's just as easy to search through a string for a section of it.
All you need to do is use the mid function to compare strings.
Example
Sentence = "Hi. I am a Human!"
Searchstring= "Human"
SentenceLength = len(Sentence)
SearchLength = len(SearchString)
for t = 1 to SentenceLength - SearchLength
test = mid(Sentence, t, SearchLength)
If test = SearchString then
condition = true
exit for
endif
next t
This loop or something like it will search any length of string for any substring. You could build this into a function which you can call from any point in your program. Unless you have a good reason to convert your sentence into arrays, don't bother.