I am trying to have an overall understanding of how the spelling dictionaries work and how they interact with each other. I have not come across one place that explains all of this. It would be helpful to know if my following assumptions are correct and if there are some important facts that I am missing. Here is what I understand:
For each language, there is a main dictionary (containing many words) that we do not have access to.
In addition, under “User-defined dictionaries” in the Writing Aids dialogue, there is a dictionary for a specific language, such as en-US [English (USA)], and another dictionary called Standard.
By default, the en-US dictionary comes with some words, but not as many as in the main dictionary. We can edit, add, and delete words in that dictionary.
By default, when we add words while conducting a spell check, the words are added to the Standard dictionary. We can also edit, add, and delete words in that dictionary. (So why are both en-US dictionary and Standard dictionary needed?)
We can create a new user-defined dictionary with a specialized vocabulary, such as for IT or medicine.
When we run a spell check after creating a new dictionary, we are given a choice of which dictionary to save a new word to.
The new Grammar By feature in LibreOffice 6.0 is only available after we create a new dictionary.
All user-defined dictionaries are associated with either one language or with all languages. We cannot choose to associate one with two languages at the same time, such as both UK and US English. However, we can readily change the language the dictionary is associated with.
All dictionaries associated with a specific language are in operation when that language is being used.
What do I have wrong? What am I missing?