Those 300 words were first identified decades ago as the most used English words, or high frequency (HF) words. They make up half of all the words on a printed page and are listed at the end of the Letters and Sounds handbook.
As they are so common, the sooner children can read them all fluently, the less they struggle with their reading overall. In their own writing, children invariably constantly want to use many of them too. So once they can spell all those, they make fewer spelling mistakes.
Half of them have simple spellings and are easily taught in initial phonics lessons. But as with most English words, half of them contain one or more letters which are not predictable for spelling. Quite a few of them contain letters with more than one possible pronunction as well. Children take longer to learn to read those fluently than they do 'a fat cat sat on a mat'.
In the first 100 most HF words, 40 are not entirely decodable:
the - he, be, we, me, she,
was, want, all, call, said,
of, to, one, come, do, down, into, look, now,
only, other, some, two,
could, you, your,
when, what, where, which, who, why,
there, were,
right, are, have, before, more.
In next 200, 55 are clearly tricky:
another, any, many, saw, water, small, laughed,
bear, great, head, ready,
ever, never, every, eyes,
find, friends, giant, I’ll, I’m, key, live, river,
people, pulled, put, thought, through, were, work, would,
coming, everyone, gone,
most, mother, oh, once,
grow, how, know, snow, town, window,
book, food, good, room, school, soon, too, took, door,
Mr Mrs
Another 13 are slightly so (partly depending on accent):
after, asked, can’t, fast, last, plants
animals, dragon, magic,
clothes, cold, old, told
The other 190 words are regular for reading and can all be used for teaching basic phonic decoding (but many, such as 'they' are not completely regular for spelling):
a, am, an, and, as, at, back, bad, can, cat, dad, gran, grandad, had, has, hat, man, rabbit, ran, sat, than, that, that’s,
came, gave, made, make, place, take, same, name, baby,
away, day, may, play, say, way,
car, dark, garden, hard, park,
bed, best, better, eggs, end, fell, get, help, let, let’s, next, red, tell, them, then, very, well, went, yes, her,
been, feet, green, keep, need, queen, see, sleep, three, tree, trees,
each, eat, sea, tea, please, even, here, these,
big, children, did, didn’t, different, fish, him, his, if, in, is, it, it’s, its, king, little, miss, still, thing, things, think, this, will, wind, wish, with,
birds, first, girl,
inside, like, liked, time, I, I’ve, cried, night, right, by, fly, my,
box, dog, fox, from, got, hot, long, lots, no, not, of, off, on, so, stop, stopped, top, floppy, across, along,
cold, old, told,
go, going, home, over, clothes,
or, for, horse, morning,
found, house, mouse, our, out, round, around, shouted, about, boy,
but, duck, fun, just, much, mum, must, run, sun, under, up, us, jumped, suddenly,
use,
their, they, new, again, air, because, began, boat, window.
Masha Bell