I just learned that according to the Chazon Ish, as brought in Orchos Rabeinu, vol. 2, p. 94, one who said Today is the first day etc. is NOT yotzi sefiras haomer (he needs to say Today is one day, as opposed to first).
However, up until now I did not know this ruling of the Chazon Ish, whose rulings I am generally particular to follow, and have been counting “first,” “second,” and so on (as I count in English). May I continue counting in the future with a bracha, even though in the past I was (apparently) not yotzi?
See Piskei Teshuvos 489-5, that you are yotza. He brings this from the sefer Meorei Ohr. He also seems to understand the story in the Orchos Rabeinu, that since the father ws only telling the son which night it is in a roundabout way, and since he didn’t want to be yotza therefore he wasn’t yotza. However we will interpret the story, in general we can’t pasken a halacha based on a story that was heard from someone, and we don’t really know all the details and circumstances.