It would be nice to replicate in other languages. In Spanish and German, reading is almost phonetic, unlike English. Anyway, from my experience with my daughter, the step from single letters to silabes is difficult.
You should think "the step from single sounds to syllables", and the way to do that is to begin with the easy syllables like "tu", "mi", "el" (not unlike the multiplication or addition tables) before moving to longer ones. [And note that M alone is not "em", it has to be "m" when learning to read - a common pedagogical mistake! M + I makes "mi" not "emi", so M must be "m".] At least that's how children are taught in…
ma, me, mi, mo, mu
pa, pe, pi, po, pu
sa, se, si, so, su
...
after a few more rows, we expected her to generalize because she is very smart, but it's harder than what we expected and we have to told her all the 21x5 cases. (The first cases were harder, and the lasts got easier.). I don't remember about the longer silabes like "pra", "bla", ... and there are weird words like "consternado" but I guess it was not obvious.