Those who have learned to read Hebrew (thankfully a phonetically pronounced written language) have been taught that a bet has a dot (a dagesh) in it, and without the dot it is a vet. Pe and fe are similar. (These letters interestingly follow Grimm’s Law - put forth by the authors of the fairy tales - governing language evolution and how we hear and speak it.)
If we learn Ashkenazic Hebrew rather than Sephardic, we also learn that a tav has a dot and a sav does not.
But why are there dots in some of the other letters?
There are three types of dot. The letters בּ, גּ, דּ, כּ, פּ, תּ nearly always have dots when at the beginning of a word or after a closed syllable. (An example of a closed syllable would be “hot” in “hotdog.” Put a dot in that “d”!)
The second type is inside a he at the end of a word, indicating feminine singular possessive.
The third type indicates letters originally doubled. For grammatical reasons, letters were doubled in some words, and historically you would have heard them pronounced with a longer sound, similar to the doubling of a consonant in Italian, for instance. (“Spaghetti” with only one “t” would not be nearly as good.) Syrian and Yemenite Jews differentiate the sounds.
Check out the words in your Siddur. And as you attend special Derekh programs at Beth Shalom, remember that the dalet in “Derekh” has a dot in it.