C.K. Ogden’s Basic English has 850 words, just enough to communicate with a global audience. Ogden’s list along with 50 international words could define or describe any word in a dictionary. Winston Churchill was impressed but Rudolf Flesch was not.
There have been arguments for and against controlled English. I would suggest a mix of control and freedom. But before I present the details, here is a new classification of words based on vocalic length. Monovowels are words that have just one vowel letter; divowels, two vowel letters; and polyvowels, three or more vowel letters.
To find the vocalic length of a word, count all occurrences of a e i o u. Now y must also be counted if a syllable of a word has no a e i o u. Here are some examples: rhythm (monovowel; y is counted), stay (monovowel; only a is counted) youth (divowel; only o and u are counted), agony (polyvowel; a o and y are counted).
My first assumption is that polyvowels contribute to reading difficulty with the exception of those found in the Ogden’s list. My second assumption is that all monovowels and divowels are easy to read whether they be present in Ogden’s list or not. As I suggested before, let us have a mix of freedom and control: freedom to use any monovowel or divowel; and control, to use only the words in the following list of Basic Polyvowels, consisting of just 212 words from Ogden’s list:
about account addition adjustment advertisement agreement again against amount amusement animal apparatus approval argument association attention attitude attraction authority automatic awake (21 words)
balance beautiful because before behaviour belief between boiling building business (10 words)
camera carriage cause certain cheese chemical colour committee community company comparison competition complete computer condition connection conscious country culture curtain cushion (21 words)
damage daughter decision degree delicate dependent desire destruction detail development different digestion direction discovery discussion disease distance distribution division (19 words)
education elastic electric engine enough environment equal every example exchange existence expansion experience (13 words)
family feather feeble feeling female fertile fiction foolish frequent future (10 words)
general government guide (3 words)
harbour harmony healthy hearing helicopter heredity history hospital house humour (10 words)
idea important impulse increase industry instrument insurance interest invention (9 words)
journey (1 word)
knowledge (1 word)
language learning leather library liquid loose (6 words)
machine manager married material measure medical meeting memory military minute motion mountain (12 words)
nation natural necessary needle noise (5 words)
observation office operation opinion opposite orange organisation ornament (8 words)
parallel peace physical picture please pleasure poison political position possible potato private probable produce property punishment purpose (17 words)
quality question quiet quite (4 words)
reaction reading ready reason receipt regular relation religion representative request responsible (11 words)
science secretary selection separate serious sneeze society special square statement station structure substance suggestion surprise (15 words)
teaching technology tendency theory together tomorrow tongue trousers trouble (9 words)
umbrella (1 word)
value violent voice (3 words)
waiting weather (2 words)
yesterday (1 word)
NOTE: The Basic Polyvowel Words may be used as a spelling scale too by administering a vocalic cloze test based on this list of just 212 words.