[Here is one of many application notes for the 555. It shows various uses of the 555.
For what you want to do, you need memory as Mee-n-Mac notes. A relatively simple way to do it is with shift registers. You will need one S-R bit for each element of “i love you.” At an average of 3(?) dot/dash elements per alphabetic character, you need around 30 bits, or four 8-bit shift registers. Each output bit would trigger a 555 to generate a dot, dash, or do nothing for a space. This simplistic method would sound odd since Morse code has a cadence of short pauses between dots/dashes and longer pauses between letters and words (not to mention the individual’s keying “fist”) but it should work.
So it is possible, but not worth it with other, much easier solutions out there.](http://www.sophphx.caltech.edu/Physics_5/Data_sheets/555appnote.pdf)