One big question which you must somehow answer is "how much of English is Anglo-Saxon and how much is Latin?" During the Norman Conquest (look it up) French-speaking people from England invaded and conquered England. There was a period of time during which the common people spoke Anglo-Saxon and the aristocracy spoke French (which is a Romance or Latin-derived language). Then, too, there was a period of time when highly educated people wrote in Latin. The result is that English has a sort of dual vocabulary that often contains short, everyday words derived from Anglo-Saxon, and longer words that are typically used in formal writing and in technical contexts. You also should read "English Is Not Normal," https://aeon.co/essays/why-is-english-so-weirdly-different-from-other-languages According to this essay, most languages have other languages with which they share "mutual intelligibility." English does not. I am told that speakers of Dutch and German can half-understand each other. English-speakers do not understand German at all, not the slightest bit; it is a completely foreign language to us. "There is no other language, for example, that is close enough to English that we can get about half of what people are saying without training and the rest with only modest effort. German and Dutch are like that, as are Spanish and Portuguese, or Thai and Lao. The closest an Anglophone can get is with the obscure Northern European language called Frisian: if you know that tsiis is cheese and Frysk is Frisian, then it isn’t hard to figure out what this means: Brea, bûter, en griene tsiis is goed Ingelsk en goed Frysk. But that sentence is a cooked one, and overall, we tend to find that Frisian seems more like German, which it is."

I think it's important to keep in mind that when one says that English is a "GermanIC" language, this does not mean that half of its vocabulary is like that of modern German. Instead, it means that English shares some vocabulary with other German-like languages: for example, Dutch, Norwegian, Danish, Swedish, Icelandic, as well as German. All of these share considerable vocabulary and in some cases grammar and pronunciation, some more than others. Historically, these languages evolved from a similar language stock. They share "roots" of words yet the pronunciation and spelling vary. In Norwegian, hvit (white), grønn (green), rød (red), hus (house), etc. are easily recognizable to an English speaker. Norwegian verbs also do not change for person as do the Romance and Slavic languages (in Spanish, yo voy, tu vas, el va, I go, you [familiar] go, he goes, etc.). Thus, in Norwegian: jeg snakker, du snakker, vi snakker, (I speak, you speak, we speak) which is closer to English verb forms which only distinguish singular and plural forms. It is true that Norwegian is closer to Swedish than it is to English but there are still loads of words in all of the GermanIC ones -- that one can easily recognize as similar to English ones. Moreover, in Dutch, the cadence of the language is very similar to English, more so than in Scandinavian languages. While it is true that English has a significant number of Latin root words that it shares with Romance languages (some of which also appear in the Slavic languages, by the way), the vocabulary, sounds, and grammar place English closer to the GermanIC (not "German") languages according to linguists who have studied the totality of these languages. Thus, what you include IN your outline, should consider the historic development of English from GermanIC as well as Latin stock, yet also keep in mind that language in general is inherently related to political as well as socio-cultural developments.

For an outline, if I were writing this, some possible subheads I would consider would be: a) What does it mean to say that a language is "Germanic?" I'd find some linguistics books and see what the "official" definitions are. b) What are some reasons for considering English to be a Germanic language? E.g. "In his 1892 book, famous linguist so-and-so said it was because of X, Y, and Z. c) What are some reasons for considering English not to be a Germanic language? I wonder if there are any computer-based studies nowadays, like "numerical taxonomy" in biology, that analyze languages and calculate similarities and differences?