You apparently have no idea what a family of languages is. The first such to be detected was the Indoeuropean family. I believe it was a Briton stationed in India in the 18th century who noticed that the languages of most of India, descendants of Sanskrit, shared surprising similarities with Latin, Greek, and the other major languages of Europe. It had been known for some time that the languages of Europe had similarities but that could be put down to their geographical proximity. Finding a relationship far off in India was something else.
Anyway, a number of such families have since been identified. Indoeuropean remains a major one. Another one, the Semitic family includes Hebrew, Arabic, Berber, and a number of ancient languages such Egyptian and Akkadian.
Note that Hebrew is Semitic. Celtic is in a whole different family, the Indoeuropean one. That's important because all the member languages of a family are more related to each other than they are to languages in any other family.
Now, that doesn't mean that families aren't related in superfamilies. The idea is not widely accepted, but a number of scholars have pointed out underlying similarities that point to these superfamilies. Even granting their existence, superfamilies don't make family relationships go away. That's what several people have tried to do on this thread when pointing out that, for instance, Hebrew has a word for earth that looks a bit like earth. That doesn't make everything Hebrew, sorry!
The problem is that a language in one family essentially will not drift across family boundaries. The Arabs conquered Persia in the 600s AD, bringing them into the emerging Muslim empire. The Persian language, Indoeuropean at root, started absorbing Semitic Arabic loanwords at a high rate. Today it has more Arabic words than Indoeuropean. For all that, the everyday core vocabulary is still after all these hundreds of years identifiably Indoeuropean. You typically don't start using loanwords for "father," "mother," "house," "daughter," "son," etc.
The closest thing to a shift across family boundaries happens when a small population is completely absorbed in a dominant culture. That's what has happened to most of the immigrants to America, at least until La Reconquista got started.
Let's take a migrant group that typically doesn't assimilate, however. The Gypsies apparently left India around 800 AD. They've been and still are everywhere. There are several variants of the Romany dialect in several parts of the world. But they're all not only still Indoeuropean, they're all still identifiably descendants of Sanskrit. It's still an Indian linguistic subfamily, all the branches, everywhere, no matter what the dominant culture or what loanwords have been incorporated along the way. That's just the way languages change. You don't obliterate your roots.
So here's the dilemma for saying that the Hebrews became the Celts. Celtic should be in the Semitic family, far more similar to Hebrew than it is to Latin. The reverse is true. It's far more similar to Latin (or Greek, or Russian, or German, or even Sanskrit) than it is to Hebrew.
You can say that a wave of Jewish migrants went to Europe and got completely absorbed in cultures that already existed there. It's a historically unimportant non-point which does not demand evidence as it would not be expected to leave any. It won't do for your thesis about Lost Tribes becoming this other group.
Your whole theory is based on this language argument. I assume you live in America. Look around you. There are descendants from Italy that don't speak a lick of Italian, Japanese-Americans that don't speak any Japanese, etc. It only takes two generations to adopt the language of the majority. As the tribes moves across Europe, they would've had to speak the languages of the surrounding peoples. Just because the British don't speak pure Hebrew doesn't mean anything. Your argument is dumb.