The code language follows a simple substitution cipher where each letter in the original word is replaced by the letter preceding it in the English alphabet. For example, 'M' becomes 'L', 'A' becomes 'Z' (wrapping around from A to Z), 'T' becomes 'S', and so on. Applying this pattern to 'CHEMISTRY', 'C' becomes 'B', 'H' becomes 'G', 'E' becomes 'D', 'M' becomes 'L', 'I' becomes 'H', 'S' becomes 'R', 'T' becomes 'S', 'R' becomes 'Q', and 'Y' becomes 'X'.