A long time ago, in the Bronze Age, there were a group of people living in Scandanavia. These people would eventually become the Germanic people. The people living then didn't really have writing. They had runes but they weren't used much. They were mostly used for ceremonial purposes like on swords or other blades.
The fact that these people didn't write many things down means that we know very little about their day to day language. They obviously spoke a language, and we can make some very educated guesses as to their language but we have very few things that directly indicate what their language was like. We don't know what their language was called, so linguists decided to call it Proto Germanic because it is the language all Germanic languages come from.
Over time these people moved around and some of them ended up in Britain. The first Germanic people arrived in Britain in the 400s. These people became known as the Anglo Saxons. They were a warrior culture and loved telling stories of battle. Beowulf, written in the 800s, is a story full of great deeds, powerful kings and fierce warriors.
The dialects of the Germanic people who came to Britain mixed together and over time a new language with new dialects began to emerge. This language is called Old English, or Anglo Saxon and is the ancestor of the language I am writing this article in. Beowulf was written in the prestigious West Saxon dialect of southern England.
In the language of the Anglo Saxons the word for "stone" was "stān". The line on the "a" indicates a long vowel. "ā" was pronounced like Modern English "ah". There were many words that used the "ā" sound. "bān" meaning "bone" is another example.
People learn language from their parents and from those around them. What might have seemed a weird pronunciation to the previous generation is considered ordinary to the current generation. In this way pronunciation can change over time without people really realising it. The word "stone" is an example of one of those changes.
Over time, the "ā" sound began to be pronounced further back in the mouth. In IPA this sound would be represented by the character "ɔ". To pronounce this sound just imagine the Queen of England saying the word "law". She and many other people in Britain use that sound in that word. This particular accent is known as Received Pronunciation or RP for short.
The sound moved further back a few centuries later to a sound represented by the IPA character "o". Finally that sound changes once more becoming the modern "o" sound found in words like "stone", "no", "grow", "home" and "bone". There are a lot of words in Modern English with the "o" sound and we can find connections to other Germanic languages that you might not realise.
We talked about Proto Germanic earlier in the article. As we said, we don't have many words from the ancestor of the Germanic languages directly recorded. But we can work them about via a process linguists call comparative reconstruction. Here we look at the oldest Germanic languages and work out what the ancestor word could have been.
The reconstructed word for "stone" in Proto Germanic is *stainaz. A star is placed before the word to indicate that we don't have direct evidence of it, but rather that we reconstructed it from the older Germanic languages. We can see "ai" in the Proto Germanic word which was pronounced like Modern English "eye". The sound changed in the development of German, but it eventually became "ei" in Modern German, pronounced the same as Modern English "eye".
If a language keeps the word from its ancestor then that word will follow the sound shifts that happen through the centuries. This means that if we can find a word in the modern language with "ei", then that word might be descended from a Proto Germanic word with "ai" in it.
But of course, languages are not only messy but also complicated. Not all words that contain "ai" in Proto Germanic become words with "o" in Modern English and not all words in Modern German with "ei" come from a word in Proto Germanic with "ai" in it. For instance, Proto Germanic *mīnaz became "mein" in German and "mine" in English. So a word with "ei" in Modern German might come from a Proto Germanic word with "ī" in it. So "ī" and "ai" in Proto Germanic eventually started being pronounced the same as the language developed into Modern German. This is an example of a vowel merger.
And the difficulties don't stop there. Not all words in Proto Germanic with "ai" became words with "ā" in Old English. "Wheat" for instance comes from Old English hwǣte where the "æ" character represents the "a" sound in Modern English "cat" or "mat". The Proto Germanic word for it is *hwaitijaz which became "Weizen" in German.
But despite all the messiness, we can still find many examples of words with "o" in English and "ei" in German. Here are some of them.
English German Proto Germanic
stone Stein *stainaz
home Heim *haimaz
oak Eiche *aiks
oath Eid *aiþaz
bone Bein *bainaz
dole Teil *dailą
token Zeichen *taikną
ghost Geist *gaistaz
foam Feim *faimaz
loaf Laib *hlaibaz
mole Meil *mailą
stroke Streich *straikaz
goat Geißbock *gaits
load Leite *laidō
row Reihe *raiwō
soap Seife *saipǭ
There are many other interesting connections between these languages, not just in the vowels but also in the consonants. But I guess those will just have to wait for another time