When we say :

  • Specify, it becomes Specification (no t)

  • Value, it becomes Valuation (no t)

  • Custom, it becomes Customization (no t)

Lemma is a code used in programming, to describe the process of doing this Lemma, the word used is "Lemmatization".

I wonder where did the "t" in Lemmatization come from?


  • 10
    Among the three words, you've got ication, ation, and tization added—so there's more different between those than just the t. I also note that both specify and value lose their last letter before the rest is added, but that lemma does not. Maybe it would be a more direct comparison if you gave custom → customization as one of the examples? (Although even then, that word ends in a consonant rather than a vowel.) So far, I haven't seen a pattern of any kind for a direct comparison between the base words and what's added—so, lemma doesn't stand out as an exception . . . – Jason Bassford Jul 21 '19 at 4:34
  • 3
    Note that the root for specify is specific. – marcellothearcane Jul 21 '19 at 7:31
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    Because "lemmaize" would be difficult to pronounce clearly. Generally speaking, when "izing" a word that ends in a vowel the "t" is added to separate the syllables (or some longer root is used which provides the needed consonant). – Hot Licks Jul 21 '19 at 11:51
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    This was a really weird thing to be wonder about, in my opinion. Definitely +1 for that. It's nerdiness level 100 on this one and I'm filled with utmost admiration and respect. May I inquiry as to how you came up with it? What made you consider such a immensely useless thing (still being information gold nugget)? I'm so impressed... – DonkeyBanana Jul 21 '19 at 14:04
  • @DonkeyBanana Lemmatization sounds like Limitization except Limitization origion "Limit" has T, Why would Limit end up similar to Lemma ?! – asmgx Jul 22 '19 at 1:31

"Lemma" is from a Greek word that had t in some of its forms

Etymologically, the t in lemmatize comes from the stem of the Greek word λῆμμα, which is the source of the English word lemma. Greek nouns have many inflected forms: the citation form λῆμμα is just the nominative (and accusative) singular form. Most other forms of a Greek noun are built on a stem that often differs at the end from the nominative singular form. Greek has many neuter nouns ending in -μα (-ma) with stems ending in -ματ- (-mat-). Conventionally, the inflected form used to identify the stem of a Greek noun is the genitive singular, which for λῆμμα is λήμματος (lemmatos). By removing the -ος, you can identify the stem lemmat-. The nominative and accusative plural λήμματα (lemmata) is built on the same stem.

Some other English words follow the same pattern

Most English speakers don't know these kinds of details about the etymology of words like lemma or about how Greek nouns inflect. They just memorize the form of the English word lemmatize, possibly aided by analogy with other pairs of similarly related words.

A number of other Greek -μα nouns have entered English as -ma nouns and show the same variation with -mat- in derived words:

  • stigma, stigmatize
  • asthma, asthmatic
  • trauma, traumatic, traumatize
  • aroma, aromatic, aromatize
  • enigma, enigmatic
  • cinema, cinematic
  • drama, dramatic, dramatize

There are also some English nouns ending in -m that are from Greek neuter nouns ending in -μα and that are related to words containing -mat-:

  • system, systematic, systematize
  • problem, problematic, problematize
  • emblem, emblematic
  • symptom, symptomatic
  • sperm, spermatic

But custom is not such a noun. I don't think there's any easy way to figure that out aside from looking up its etymology.

/t/ is not just automatically inserted after any vowel followed by -ize, although there might be some non-automatic tendency towards /t/-insertion in certain contexts

As I mentioned, most speakers are not aware of the etymological source of the t in lemmatize.

Some comments and answers have brought up an idea that from a synchronic (as opposed to diachronic) perspective, the /t/ in lemmatize could be analyzed as a consonant that is inserted to prevent hiatus (a sequence of two vowels in separate syllables with no intervening consonant).

I don't think that's an untenable hypothesis, but I wanted to say that any such process of /t/-insertion before -ize is not incredibly productive, and is more limited than just a rule like "-tize is used after vowels".

Looking at other words ending in /ə/ spelled -a, we see the following alternatives to inserting /t/ before -ize:

  • hiatus with a possible change in vowel quality (that could be viewed as introducing a front glide):
    algebra > algebraize /-eɪaɪz/ or /-əaɪz/

  • dropping the first vowel:
    formulize, silicize, nebulize, patinize

If we look at other vowels, we also see those alternative strategies being used fairly frequently. Dropping the first vowel is very common with bases ending in /i/:

  • jeopardize, scrutinize, summarize, agonize, theorize, notarize, anatomize, empathize, eulogize, prioritize, botanize, alchemize, etymologize, militarize, melodize, theologize, lobotomize, strategize, astronomize, philosophize, memorize, allegorize, sorcerize, prioritize

For bases ending in /oʊ/, hiatus (which could be viewed as involving a back glide) seems no less common than t-insertion. Hiatus occurs in ghettoize, heroize, jumboize, and memoize. The only case of t-insertion after /oʊ/ that I know of is egotize, which coexists with a less frequent alternative form with hiatus, egoize.

For non-rhotic speakers, there are a great many words ending in the sound /ə/ with spellings that end in the letter R. When such words are suffixed with -ize, the consonant sound /r/ is inserted after the /ə/, as in the following list:

  • characterize, rubberize, rasterize, vulgarize, vascularize, exteriorize, valorize, factorize
  • 4
    In addition to the Greek derivation (which I really didn't know about until now), there's the fact that it's just easier to pronounce. Try wrapping your tongue around "lemmaize". "stigmaic", &c. – jamesqf Jul 21 '19 at 17:55
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    The glottal stop that would be outright required in lemma'ize isn't probably not by coincidence an allophone of t in various accents that have t-glottalization. – vectory Jul 21 '19 at 21:10
  • 1
    @jamesqf: There are some words that end in -aize or -aic, like Judaize and Judaic, archaize and archaic, algebraize and algebraic. The -a- in these words is not pronounced the same as a word-final -a. Another possibility for words with final -a is for the derived word to remove the -a, as in silica, silicic or chimera, chimeric. – herisson Jul 21 '19 at 21:26
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    Lovely to see some Greek on a Monday morning. I wanted to see "schema, schematic" in your list though, as it's a favourite word of mine. – Phil M Jones Jul 22 '19 at 8:40
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    @GregSchmidt Who says it's not? – Andrew Leach Jul 23 '19 at 18:13

Etymonline states:

1560s, in mathematics, from Greek lemma (plural lemmata) "something received or taken; an argument; something taken for granted,"
(emphasis mine)

This is where the 'T' comes from. In addition, note that lemma derives from Greek, whereas your other examples come from Latin through French. This would account for the difference in forms.


You’re confusing the issue by including “-ation”.  Your question boils down to this:

  • “Specify” is a verb; it becomes “specification”⁠ (no added “t”).

  • Value is often a noun, but it can be used as a verb (see American Heritage Dictionary, Lexico, and Collins English Dictionary).  But “valuate” means (approximately) the same as the verb form of “value”, so it’s no surprise that we get “valuation”⁠ (no added “t”).         Related Ngram

  • “Custom” is a noun and an adjective.  The verb form is “customize”, so it becomes “customization”⁠ (no added “t”).

  • The verb for the process of doing making a “lemma” is “lemmatize”.

What’s happening is:

  • We add the suffix “-ize” to a noun to get a verb meaning “to make or become”, as discussed in What is the difference between the suffixes -ize and -ify?
  • But “lemmaize” would be hard to read and pronounce.  Spelling it “lemmaïze” or “lemma–ize” wouldn’t help much.  When we add “-ize” to a noun that ends with a vowel, we inject a “t” to make it readable and pronounceable.  Other examples include “dramatize”, “anesthetize”, “monetize”, “stigmatize” and “traumatize”.


  • ”lemma” + “ize” → “lemmatize”
  • “lemmatize” → “lemmatization”

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