Answers.Body: <p>It is very confusingly worded, and I would think it's incorrect according to linguistic terminology.</p>
  <p>A <em>lemma</em> is the canonical form of a word, commonly the infinitive of a verb, the nominative singular of a noun, and the positive of an adjective. The <em>inflected forms</em> belonging to a word would the the forms used for other tenses and persons etc for verbs, case and number for nouns, and comparative/superlative for adjectives.</p>
  <p>This raises the question of what a <em>word</em> is, and there is no satisfactory answer to this, even more than 100 years after the foundation of modern linguistics...</p>
  <p>Anyway, the 'boldface form' (a term I have not come across in 30 years as a linguist), refers to <em>dictionary headwords</em>, which are lemmas. There are some lemmas that are 'shared' by words which have multiple meanings: the common example in linguistics is <em>bank</em>, which can be a financial institution, the side of a river, a term to describe the process of tilting the wings of an airplane in flight, or it can mean to deposit an amount of money in an account, etc. All these words you would find under <strong>bank</strong> in a dictionary, but usually under several different entries. So I guess this is what is meant by &quot;multiple boldface forms&quot;. However, these are usually completely unrelated words which by accident share the same spelling; in some cases it could also have been the same word that then developed different meanings.</p>
  <p>To summarise: the paragraph you quote is plain wrong/sloppy in its use of terminology, as a dictionary headword <em>is</em> a lemma in every dictionary I have seen, but these are not unique, as several different words might have lemmas which are spelled the same way (but they are still <em>different</em> lemmas — no single word would have multiple dictionary entries).</p>
  <p>For example:</p>
  <ul>
  <li><strong>bank</strong> (bank, banks), noun: a financial institution</li>
  <li><strong>bank</strong> (bank, banks), noun: the side of a river</li>
  <li><strong>bank</strong> (bank, banks, banked, banking), verb: tipping the wings of an airplane</li>
  <li><strong>bank</strong> (bank, banks, banked, banking), verb: depositing money in an account</li>
  </ul>
  <p>We have four lemmas (in bold), two of which have two inflected forms, and the other two have three each. These are also four different words, with a total of four different word forms (<em>bank</em> and <em>banks</em> are common forms of all words)</p>
  <p>Often, to avoid confusion, you would refer to them as <span class="math-container">$bank_1$</span> for the financial institution, and <span class="math-container">$bank_2$</span> for the river bank, etc. to indicate that they are different words.</p>
  <p>You can probably see that English has a number of lemmata (which is the proper plural of lemma, since it's of Greek origin) which is by a factor of 3-4 smaller than the number of word types, whereas in other languages this ratio will be a lot smaller, as they have more inflected variants. An English noun has just singular and plural forms, whereas a German noun would have singular and plural across each of four cases (though some of them would share the same word forms).</p>
  
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Answers.CreationDate: 2021-09-03T14:13:01.137Z
Answers.Text: are they different forms though? they seem like the same form repeated 4 times.
Answers.UserDisplayName: Criticize SE actions means ban
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Answers.Text: @user253751 They _look_ the same, but are different words. Their meaning is unrelated, and they have different origins. The financial bank comes from Italian _banca_ (table), the river bank from Old Danish _banke_ or Old Norse _bakki_. It is 
   just chance that we spell them all _bank_.
Answers.UserDisplayName: Oliver Mason
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Answers.CreationDate: 2021-06-28T08:23:52.770Z
Answers.LastActivityDate: 2021-06-28T08:23:52.770Z
Answers.UserDisplayName: Oliver Mason
Answers.Body: <p>Here are some examples: <em>reducing</em> or <em>reduces</em> or <em>reduced</em> or <em>reduction</em> -&gt; <em>reduce</em>; <em>am</em> or <em>are</em> or <em>is</em> -&gt; <em>be</em>; <em>n't</em> -&gt; <em>not</em> and <em>'ve</em> -&gt; <em>have</em>.  When using spacy, the token can be referenced to find the lemmatized root.</p>
  <pre><code>lemmas =[token.lemma_ for token in doc]
  lemmas =[lemma for lemma in lemmas
         if lemma.isalpha() or lemma == '-PRON-'
         ]
  
  
  I use lemma to find parts of speech
  </code></pre>
  <p>Wiki</p>
  <p>In computational linguistics, lemmatisation is the algorithmic process of determining the lemma of a word based on its intended meaning. Unlike stemming, lemmatisation depends on correctly identifying the intended part of speech and meaning of a word in a sentence, as well as within the larger context surrounding that sentence, such as neighboring sentences or even an entire document</p>
  
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Answers.CreationDate: 2021-06-28T15:25:41.137Z
Answers.Text: That's not quite correct: _reduction_ is a base form in itself, not an inflected form of _reduce_. You're probably thinking of stemming, which is similar to lemmatisation, but also includes derivations rather than just inflections.
Answers.UserDisplayName: Oliver Mason
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Answers.CreationDate: 2021-06-28T16:17:04.260Z
Answers.Text: Lemmatisation is also not grouping words together. It is a mapping from a word form to a canonical form, which in English can be achieved by removing inflectional morphemes (such as a plural marker _-s_ for a noun).
Answers.UserDisplayName: Oliver Mason
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Answers.Text: explain what a canonical form is
Answers.UserDisplayName: Golden Lion
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Answers.Text: It's the base form. Nominative singular for nouns, infinitive for verbs, positive for adjectives.
Answers.UserDisplayName: Oliver Mason
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Answers.LastActivityDate: 2021-06-28T17:52:23.883Z
Answers.LastEditDate: 2021-06-28T17:52:23.883Z
Answers.UserDisplayName: Golden Lion
Body: <p>Number of lemmas can be used as a rough measure for the number of words in a language. A lemma can have multiple word-form types. It can be understood from the following paragraph taken from p12 of <a href="https://web.stanford.edu/%7Ejurafsky/slp3/2.pdf" rel="nofollow noreferrer">Regular Expressions,Text Normalization, Edit Distance</a></p>
  <blockquote>
  <p>Another measure of the number of words in the language is the number
  of lemmas instead of wordform types. Dictionaries can help in giving
  lemma counts; dictionary entries or <strong>boldface forms</strong> are a very rough
  upper bound on the number of lemmas (<strong>since some lemmas have multiple
  boldface forms</strong>). The 1989 edition of the Oxford English Dictionary had
  615,000 entries.</p>
  </blockquote>
  <p>It is also given that a lemma can have multiple boldface forms, what are the boldface forms referred here? Are they different from wordforms?</p>
  <p>If possible, provide an example for lemma having multiple boldface forms.</p>
  
Tags: <natural-language-processing><books>
Title: Example of lemma having multiple boldface forms
UserDisplayName: hanugm
ThreadText: # Example of lemma having multiple boldface forms
  
  (Asked by: username_0 on 2021-06-27)
  
  Number of lemmas can be used as a rough measure for the number of words in a language. A lemma can have multiple word-form types. It can be understood from the following paragraph taken from p12 of [Regular Expressions,Text Normalization, Edit Distance](https://web.stanford.edu/%7Ejurafsky/slp3/2.pdf)
  
  > Another measure of the number of words in the language is the number
  > of lemmas instead of wordform types. Dictionaries can help in giving
  > lemma counts; dictionary entries or **boldface forms** are a very rough
  > upper bound on the number of lemmas (**since some lemmas have multiple
  > boldface forms**). The 1989 edition of the Oxford English Dictionary had
  > 615,000 entries.
  
  It is also given that a lemma can have multiple boldface forms, what are the boldface forms referred here? Are they different from wordforms?
  
  If possible, provide an example for lemma having multiple boldface forms.
  
  **Tags:** natural-language-processing, books
  
  ---
  
  ## 2 answers
  
  ### Answer by username_1 on 2021-06-28. Score: 3
  
  It is very confusingly worded, and I would think it's incorrect according to linguistic terminology.
  
  A *lemma* is the canonical form of a word, commonly the infinitive of a verb, the nominative singular of a noun, and the positive of an adjective. The *inflected forms* belonging to a word would the the forms used for other tenses and persons etc for verbs, case and number for nouns, and comparative/superlative for adjectives.
  
  This raises the question of what a *word* is, and there is no satisfactory answer to this, even more than 100 years after the foundation of modern linguistics...
  
  Anyway, the 'boldface form' (a term I have not come across in 30 years as a linguist), refers to *dictionary headwords*, which are lemmas. There are some lemmas that are 'shared' by words which have multiple meanings: the common example in linguistics is *bank*, which can be a financial institution, the side of a river, a term to describe the process of tilting the wings of an airplane in flight, or it can mean to deposit an amount of money in an account, etc. All these words you would find under **bank** in a dictionary, but usually under several different entries. So I guess this is what is meant by "multiple boldface forms". However, these are usually completely unrelated words which by accident share the same spelling; in some cases it could also have been the same word that then developed different meanings.
  
  To summarise: the paragraph you quote is plain wrong/sloppy in its use of terminology, as a dictionary headword *is* a lemma in every dictionary I have seen, but these are not unique, as several different words might have lemmas which are spelled the same way (but they are still *different* lemmas — no single word would have multiple dictionary entries).
  
  For example:
  
  * **bank** (bank, banks), noun: a financial institution
  * **bank** (bank, banks), noun: the side of a river
  * **bank** (bank, banks, banked, banking), verb: tipping the wings of an airplane
  * **bank** (bank, banks, banked, banking), verb: depositing money in an account
  
  We have four lemmas (in bold), two of which have two inflected forms, and the other two have three each. These are also four different words, with a total of four different word forms (*bank* and *banks* are common forms of all words)
  
  Often, to avoid confusion, you would refer to them as $bank\_1$ for the financial institution, and $bank\_2$ for the river bank, etc. to indicate that they are different words.
  
  You can probably see that English has a number of lemmata (which is the proper plural of lemma, since it's of Greek origin) which is by a factor of 3-4 smaller than the number of word types, whereas in other languages this ratio will be a lot smaller, as they have more inflected variants. An English noun has just singular and plural forms, whereas a German noun would have singular and plural across each of four cases (though some of them would share the same word forms).
  
  > **Comments:**
  > **username_2**: are they different forms though? they seem like the same form repeated 4 times.  
  > **username_1**: @user253751 They _look_ the same, but are different words. Their meaning is unrelated, and they have different origins. The financial bank comes from Italian _banca_ (table), the river bank from Old Danish _banke_ or Old Norse _bakki_. It is   just chance that we spell them all _bank_.  
  
  ---
  
  ### Answer by username_3 on 2021-06-28. Score: 1
  
  Here are some examples: reducing or reduces or reduced or reduction -> reduce; am or are or is -> be; n't -> not and 've -> have.  When using spacy, the token can be referenced to find the lemmatized root.
  lemmas =[token.lemma_ for token in doc]
  lemmas =[lemma for lemma in lemmas
         if lemma.isalpha() or lemma == '-PRON-'
         ]
  
  
  I use lemma to find parts of speech
  
  Wiki
  In computational linguistics, lemmatisation is the algorithmic process of determining the lemma of a word based on its intended meaning. Unlike stemming, lemmatisation depends on correctly identifying the intended part of speech and meaning of a word in a sentence, as well as within the larger context surrounding that sentence, such as neighboring sentences or even an entire document
  
  > **Comments:**
  > **username_1**: That's not quite correct: _reduction_ is a base form in itself, not an inflected form of _reduce_. You're probably thinking of stemming, which is similar to lemmatisation, but also includes derivations rather than just inflections.  
  > **username_1**: Lemmatisation is also not grouping words together. It is a mapping from a word form to a canonical form, which in English can be achieved by removing inflectional morphemes (such as a plural marker _-s_ for a noun).  
  > **username_3**: explain what a canonical form is  
  > **username_1**: It's the base form. Nominative singular for nouns, infinitive for verbs, positive for adjectives.  
  
  ---
  
  