testSentence = "This is a TEST sentence."
lexicon = {}

for line in io.lines("lexicon.txt") do
    key = string.match(line, ".- ")
    if key ~= nil then lexicon[key] = string.match(line, " (.*)") end
end

words = {}
for word in testSentence:gmatch("%S+") do
    table.insert(words, word)
end

print(lexicon["value"])