When German is your mother tongue

Often, our most careful English-users claim English as their second language.
Horst, who gave no surname, is an example. In July, he wrote: “German was my first language. I took it upon myself  to try to master English the best I could growing up, so I learned the logic of stuff like media being the plural of medium, etc., while other English language speakers often couldn’t care less about such nuances.”
As a German-speaker, Horst has another big advantage. He knows when to use the objective case. That is, he would never say, “John waited at the bus stop for Christine and I.”
In the above example, the preposition, “for,” indicates that “me” and not “I” is the required pronoun. Prepositions are those small words we use to introduce phrases that tell about condition, time, place, manner, association, degree, etc. Examples of prepositions are: with, in, on, beside, under, of, to, about, for, to name a few.
German is a “declined” language. That means nouns, pronouns, adjectives, and so on, take different forms depending on whether they are subjects of a sentence or objects. The form of these words also varies if they are singular or plural. This declination (change) is known as “inflection.”
Old English, which was still very close to its Germanic roots, was a highly inflected language. Over the centuries, it almost completely lost that characteristic.  Today, we find inflection mainly in pronouns — they/them/their/theirs. The only changes affecting nouns occurs when they are pluralized or become possessives.
Oxford’s Companion to the English Language defines declension as: “A term used to describe the case system of nouns and other words in a sentence. In linguistics, case points to the pattern of inflection of such words.”
This is an important function because, in English, there are a mere three ways we are able to influence words so as to clarify meaning. These ways are: 1) word order; 2) additional words; 3) alteration of the word itself (inflection or case).
Alteration is called “case” when it affects nouns, pronouns, or adjectives. Usually, these alterations consist of modified endings — they/them/theirs (pronouns); farmer/farmers/farmer’s (nouns); tall/taller/tallest (adjectives).
The way we learn a language — its vocabulary and its grammar — is by speaking it. Clearly, since Horst first spoke a declined language, he was sensitive to endings long before he took it upon himself to speak good, grammatical English. He knew about case and understood the role of the preposition even if he was unaware of this understanding. Probably, Horst’s biggest difficulty with English was word order. But, since he learned English as he was growing up, he likely doesn’t remember encountering such a problem.
German is the mother tongue of some 95- to 100-million people worldwide. Oxford ranks it 10th among world languages in the number of speakers.  But it is first in Western Europe where it is the official language of Germany and Austria and one of the official languages of Switzerland and Luxembourg. Related languages include English, Dutch, Frisian, the Scandinavian languages, Yiddish, and Afrikaans.