"The boy is reading."
The difference is that כ is pronounced either as /k/ or /x/, the guttural sound in loch; and ק is always /k/. א is pronounced as /ʔ/, which is basically when you quickly stop the airflow in your throat, or it can act as a vowel holder, and ע is technically pronounced /ʕ/, which is like a voiced breathy sound, but most every native Hebrew nowadays pronounces it exactly the same as א. As for niqqud, Duo has them when they help to disambiguate between two spellings that would otherwise be identical, for instance רואֶה vs. רואָה, or שותֶה vs. שותָה. Sorry if any of that was confusing, just tell me if it was and I'll be happy to clarify. :)