I keep hitting roadblocks researching my grandparents and their ancestors.

[no_hypocrisy]

What exactly happened when they immigrated here from Lithuania, the Russian Empire, etc.?

Specifically, all I can find is their "American names," not their original birth names. I tried to extrapolate potential Hebrew names without much luck.

Were they told when they registered to live here that their past lives had died with their past names and from this point forward, the names they were given were their only names?

I know my great grandparents were not named Louis and Jeanette and my grandmother was not named Ida. And because either the officer was dyslectic or just gave out Americanized versions of last names, I'm stuck with a two-generation surname.

I WANT TO KNOW WHO I AM!!!!

[Donkees]

1. ''Louis and Jeanette" ...

Jeanette (Lithuanian: Žaneta)
Louis (Liudvikas)

https://www.familysearch.org/en/wiki/Lithuania_Naming_Customs

Immigrants often changed their surnames to sound more American. Contrary to popular belief, this change was not made at Ellis Island. Within a Lithuanian community, such as the local parish, immigrants may continue to use the original name, while at the same time using English-language equivalents when dealing with local government, census takers, and other English speakers.
Different branches of the same family may adopt various surname spellings. Prior to 1900, formal surname changes documented in local court records are relatively rare. Most surname changes occurred naturally over time.During the early 20th Century, especially the World War I era, surname changes are recorded more frequently, as immigrants or, more often, their children, tried to adopt more neutral surnames.

A child in Lithuania is usually given one or two given names. As well as modern names, parents can choose a name or names for their child from a long list of traditional names; these include: Christian names, i.e. Biblical names or saint's names. Lithuanian common nouns or hydronyms used as names. There are popular names constructed from the words for celestial bodies (Saulė for the Sun, Aušrinė for Venus), events of nature (Audra for storm, Aušra for dawn, Rasa for dew, Vėjas for wind, Aidas for echo), plants (Linas/Lina for flax, Eglė for spruce), and river names (Ūla, Vilija for River Neris). invented names from literature.
names of Lithuanian pagan deities and mythological figures.

There are some popular names of gods and goddesses from Lithuanian mythology that are used as personal names, such as Laima, goddess of luck, Žemyna, goddess of earth, Gabija, goddess of fire; Žilvinas, a serpent prince from the fairy tale Eglė the Queen of Serpents, Jūratė, goddess of the sea, and Kastytis, from the legend about Jūratė and Kastytis. A distinctive practice dominated in the ethnic region of Lithuania Minor, then part of East Prussia, where Lithuanized German personal names were common, such as Ansas (Hans), Grėtė (Gretchen), Vilius (Wilhelm) among Prussian Lithuanians. Some of them are still in use among Lithuanians.

[ShazzieB]

3. Very intreresting!

Within a Lithuanian community, such as the local parish, immigrants may continue to use the original name, while at the same time using English-language equivalents...

I have a feeling the Lithuanians were not the only ones who did this. My husband's family were Polish on both sides. All of his grandparents were immigrants, but his parents were born and grew up in a Polish neighborhood in Chicago.

My father in law was baptized in a Catholic church in that Polish neighborhood. We have a copy of his baptismal certificate that shows his first and middle names as Stanislaus Boleslaus. I was really surprised when I first saw it, because I knew him as William Paul [Lastname].

[Donkees]

4. ''Stanislaus Boleslaus'' are the Latinized spellings on the Baptismal Certificate

compared to the Polish alphabet spelling: ''Stanisław Bolesław''

It was common practice to be named after the saints on whose 'name day' you were born. The Baptismal Certificate wasn't a legal document as a Birth Certificate would be in the U.S. Maybe it once was in the old country. Similar to a 'Confirmation Name' you choose a name for yourself, but don't use it legally.

Some of these alphabets had additional letter sounds, such as with slashes/accents/dots/hooks, those sounds were lost when names were spelled in U.S. documents.

The Polish alphabet. Grey indicates letters not used in native words.

[sybylla]

2. The frustration is real.

It's also doubly hard if you're dealing with cyrillic or other alphabets.

I got lucky with a family in Hungary. The census had both alphabets and all entries in 3 languages, one of them being German. I could read through the entire census for the city they were from and have a chance of finding them.

Have you tried the old RootsWeb bulletin boards that became part of Ancestry? In the old days, you could look for a Lithuanian help page. There you could be given likely birthname possibilities, links to possible resources in English, translation help, and more.

I got a load of help on my Swiss ancestry at RootsWeb.