ME you need at least two, better three packs to be able to play properly. For example, it is at Mama + Papa + grandmother, grandfather, etc. rather quickly just with the vowels ..
Yet have very annoyed at Amazon because it, in local toyshop considerably cheaper are the letters, as I afterwards discovered by chance (cheaper for EUR 6, almost a quarter!). Otherwise I always compare prices before, here I had not done it. Well, again learned something. No longer blind to Amazon prices leave! So it was my own fault.