Q. Our elderly grandfather although of sound mind can hardly speak. In truth only we his children actually understand what he is saying. Can he still count Sefira with a brocho since practically he does not speak anymore?
A. See question 782 and 3120 regarding someone counting for a chole (sick) who can’t speak, but is aware and just moves his lips, if he is yotze, we wrote: “Shulchan Aruch (O.H. 489: 1) rules that it is a mitzvah for each individual to count Sefiras Haomer for himself. Mishna Berura (ibid. 5) explains that although from the verse “Usfartem Lachem” (You shall count for yourselves) it would seem that Sefira is different from any other mitzvah of speech, such as Kidush or Havdala, where we uphold that listening to others is tantamount to saying oneself, (Shomea Keone) however, some Poskim opine that they are the same and after the fact you comply just by listening. In Biur Halocho (ibid.) quoting the Pri Megodim, he rules that even after the fact, it is better to repeat the Sefira by himself without a brocho.”
Horav Shlomo Miller’s Shlit’a opinion is that in our case since at least a few understand what he is saying, he can count with a brocho.
Rabbi A. Bartfeld as revised by Horav Dovid Pam, Horav Aharon Miller and Horav Chanoch Ehrentreu Shlit’a