You can speak a sentence in many different ways. The same words can be expressed to have different meanings. Many times, a word is emphasized in order to distinguish it from an alternate word. Consider the following sentence:
He walked down the street.
When spoken aloud, the sentence might convey different meanings. “HE walked down the street” could contrast against someone else walking down the street. “He WALKED down the street” instead of running down the street. “He walked DOWN the street” instead of up the street. And “He walked down the STREET” instead of on the sidewalk.
Even a simple sentence from John 1:26: “…I baptize with water” can take on different emphasis. “*I* baptize with water” with the emphasis on himself as opposed to anyone else. Or “I BAPTIZE with water” instead of sprinkling with water perhaps? Or “I baptize with WATER” instead of what the one coming after him baptizes with which is the Holy Spirit.
So translators from the original Greek or Hebrew languages have a tough enough time just getting out the meaning of the words. We who attempt to read them aloud are also challenged with interpreting the meaning of the sentences by placing the emphasis on the proper words.