This is good work. I like what you have done, but I take one exception. The call to Morsee use a variable "intervail" which passes the dot time to the routine. Thus setting the words per minute rate. This number is rather obscure. I would propose that you do the math for the user. As long as you writing the library to make this easy for the user, do the whole job ... This is an output routine, we start up a serial routine by issuing a command like "Serial.begin(9600)" so I would suggest you do the following;
(1) make "intervail" private , initialized to 0
(2) create begin() that gets called in a fashion like "myMorse.begin(wpm)" where wpm is a variable or an actual number of the Morse sending speed in words per minute. Then you do the math and set "intervail"
cheers ... BBR (n1bq)