Dashes and dots served to make Morse code work, an old system of sending urgent messages using long or short beeps or if not available, long or short flashes of light. Look it up!
It takes very little to upgrade a simple code like that into an elaborate language.
You just add one more “layer” to what is essentially, a language.
To put it simply, a few words can convey quite a lot, but when you want to express feelings, impressions and emotions, you will need the ability to combine words in a clever way or even additional words.
And you can!