Prefix Assimilation: Mangled Letters


Quick Summary

Common prefixes like in- and con- sometimes change their form in English words. The prefix roots in combine , collate and corrupt are all con-. Likewise the prefix roots in illegal and irregular are in-. This disguising of prefix roots is called prefix assimilation.

That Poor Mangled 'N'

To expand your vocabulary skills it’s essential to learn some basic linguistic concepts. Understanding the role of these concepts in the development of English word structure will allow you to spell, learn, remember and decode words easily. Starting today some of our rootcasts will introduce these concepts in a simple, non-technical way.

You’re probably aware that prefixes are the small roots at the front of words. For example in the words control and conquer the prefix is con- meaning ‘with’ or ‘thoroughly’. But con- is also the prefix root in the words comply, collect and correct! In these words notice that the letter n of con changes forming new prefixes com-, col- and cor-. These are just disguised versions of con-. This shape-changing process is known as prefix assimilation.

Fortunately, there are just a few rules to learn to be able to recognize the most common prefix assimilations. We’ll cover two of these rules:

Rule 1 : When a prefix ending with the letter n butts up against a
root that start with the letters b, m, or p, the n becomes an m.

in + balance → imbalance
in + mobile → immobile
in + possible → impossible

con + bine → combine
con + mit → commit
con + ply → comply

Rule 2: When a prefix ending with a letter n butts up again a root that starts with a r or l , then n disappears and the r or l doubles.

in + legal → illegal
in + regular → irregular

con + late → collate
con + rect → correct

Now that you know these rules can you guess the prefix root in “symphony” ?

We have an infographic on our website that captures these rules simply, and we also have a simple mnemonic trick to help you remember these rules.

Use the mnemonic n-BiMPLeR to remember that the letter n changes when followed by one of the letters BMPLR

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