You seem to be confusing intonation with tonality. English definitely has intonation (pretty much all natural languages do), but it is not a tonal language.
Tonal languages use tonality for either inflection or for differentiating between individual words which would otherwise be homophones.
In the first case, changing the tone of a noun may change it from being a definite noun to an indefinite noun, or from singular to plural, or even in theory change its grammatical gender. Similarly, changing the tone of a verb may change its tense or switch it from being first-person to third-person.
In the second case, changing the tone completely changes the word. Mandarin Chinese (and most other Sinitic languages) is like this. Using ‘ma’ as an example, there are five possible tones in Mandarin Chinese (mā, má, mǎ, mà, and ma); each one of them corresponds to a different word (that has its own character and dictionary entry), and getting the tone wrong completely changes the meaning of the word itself (for example ‘mǎ’ is ‘horse’, while ‘mā’ is ‘mom’).
Intonation, on the other hand, is about things that are not part of the words themselves. In English, a lot of what punctuation conveys in the written language (other than pauses indicated by things like commas) is conveyed using intonation in the spoken language. For example ‘The witch is dead.’, ‘The witch is dead!’, ‘The witch is dead?’, and ‘The witch is dead...’ would all have different intonation in spoken English. The overall meaning of the sentence shifts a bit in each case, but none of the individual words change their meaning even if their intonation changes.
Intonation in English also coveys things that would require extra words to convey in the written language. Using the above example, ‘The witch is dead!’ could be an expression of jubilation over the demise of the witch, or it may be an expression of disbelief that the witch was defeated, or it may even be indicative of fury at the fact that the witch died. In the spoken language, those cases can be differentiated by the intonation of the sentence together with other things like rate of speech, lengthening of vowels, and overall volume. But just like with the earlier examples of intonation, none of the words changes in meaning just because of the differences.