Combine unique ids and turning columns into rows

I think your current layout is better than either of the two alternatives you posted, so in terms of how to Filter the records in that format, try something like this (this assumes Changed Type is the name of the previous step, change that as necessary):

    #"Filtered Rows" = Table.SelectRows(#"Changed Type", each ([Tag Name] = "English")),
    #"Filtered Rows1" = Table.SelectRows(#"Changed Type", each Table.Contains(#"Filtered Rows", [ID = [ID]]))

The first step you can do using the query wizard (just use a filter on Tag Name). The second one you'll have to do partially manually. The easiest way to do it is probably just make a step (filter something random) and then replace the code.

Hope that helps!

jahida's answer will work, and is probably more efficient than what I'm about to post. I'm only including it here because I hadn't tried a problem like yours before, and this is what I came up with. I think it's neat that there are so many ways to get to an answer with M.

I added a custom column with the formula below, also assuming that the previous step was Changed Type:

isEnglish = Table.AddColumn(#"Changed Type", "Custom", each List.Contains(Table.FindText(#"Changed Type", "English")[ID], [ID]))

That leaves you with a TRUE/FALSE column that you can filter for just TRUE to leave you with posts in English.