Oh language! Do we want to go down the route of there being no rules, just a few nebulous suggestions which change over time? Are we like the freethinking parents at sports day who declare that every child wins because they are all special? Or are we on the side of traditionalists who don’t split infinitives‏‎ and who think anyone using a preposition at the end of a sentence should be publicly flogged?

The problem is that there are so many examples of the rules of English changing over time, or being very different depending on who is doing the speaking, that it’s almost impossible to give a simple yes or no answer to any grammatical question.

So when we ask, Which is correct, on foot or by foot, it’s not all that easy to say.

on foot

Ask some traditionally minded professor at some traditional old school where they still flog students and girls are an unknown species, and he will tell you that we go:

by automobile
by steamship to the colonies
by coach
by rickshaw

but when we slip on our shoes, we go

on foot into darkest Africa
on foot to the club

Ask Michael Swan‏‎ the grammarian and he will tell you we go on foot also. Ask Google n-grams and it will tell you that around 90% of writing prefers on foot.

by foot

But language is never that simple. Ask some trendy teacher who wears flip-flops and gets the students to call him by his first name and he will tell you that we go by everything:

by eco-friendly Prius
by vegan bicycle
by methane powered bus
by foot

And check n-grams again and they tell you about 10% of modern English writing has by foot.

A Definitive Answer for TEFL Teachers

So which is it to be? You are in your TEFL class and a student asks you. What do you say?

Let’s speak practically here. If you have students taking an exam and they write:

I go to school on foot

then they will be given perfect marks. However, if they write:

I go to school by foot

then there’s a strong possibility that they could be marked down. Who knows if the teacher sitting there marking their exam paper is that same traditionally minded professor, doing some extra work for the glory of it?

So let’s keep this simple and say that on foot is never wrong and by foot could be wrong and could cost your student marks.

Useful Links

Descriptive vs Prescriptive Grammars – Talking about language and making rules. Or not.