Pronunciation Variants

About Pronunciation Variants:

In some corpora (e.g., spontaneous speech corpora), there may be different pronunciation variants that are associated with the same lexical item. For instance, the word “probably” might be variably produced as [pɹɑbəbli] (its canonical form) or as [pɹɑbli], [pɹɑli], [pɹɑi], or any of a number of other reduced forms. In the Buckeye corpus, for example, there are 290 tokens of the word “probably”, only 50 of which have the canonical pronunciation ([BUCKEYE]).

A number of studies have looked at the effects of this kind of surface variation on lexical representations (e.g., [Connine2008]; [Pinnow2014]; [Pitt2009]; [Pitt2011]; [Sumner2009]). For example, [Pinnow2014] show that lexical items with high-frequency variants that include deleted schwas have processing advantages over similar items where the deleted variant is less frequent, suggesting that frequency matters in the representations.

Because such differences may matter, PCT includes several options (Options for Pronunciation Variants:) for handling pronunciation variants in its analysis functions (though note that not every option is available in every analysis function as of version 1.1). To the best of our knowledge, none of the analysis functions we provide has ever been applied to anything other than the canonical pronunciations of forms, so it is a completely open question as to which of these options is best, or even how to determine which one might be best (e.g., in terms of correlations with other linguistic or behavioural patterns). It is simply our hope that by allowing the functions to be applied in a variety of ways, such empirical questions can be answered in the future.

Creating Pronunciation Variants:

To create a corpus that has pronunciation variants, there are several options (see also Loading in corpora). First is to use a specially formatted corpus, such as the Buckeye corpus ([BUCKEYE]), that PCT already recognizes as containing pronunciation variants. Second is to create a corpus from an interlinear gloss file that has separate lines for lexical items and their pronunciations. For example, a fragment of the text might be as follows:

Line 1:

Well, I’m probably going to go to the pool after.
wɛl ɑɪm pɹɑbəbli goʊɪŋ tu goʊ tu ðə pul æftɚ
wɛl ɑɪm pɹɑli gʌn ə goʊ ɾə ðə pul æftɚ

Line 2:

Is Max going with us?
ɪz mæks goʊɪŋ wɪθ ʌs
z mæks goʊɪŋ wɪθ ʌs

Line 3:

Oh, no, he’ll probably stay home.
noʊ hil pɹɑbəbli steɪ hoʊm
noʊ həl pɹɑbəbli steɪ hoʊm

The first line shows the spelling; the second the canonical pronunciation of each word; and the third the pronunciation of the word as it was actually said in context. This would get read in to PCT as:

spelling transcription frequency
I’m ɑɪ.m 1
is ɪ.z 1
Max m.æ.k.s 1
oh 1
well w.ɛ.l 1
after æ.f.t.ɚ 1
go g.oʊ 1
going g.oʊ.ɪ.ŋ 2
he’ll h.i.l 1
home h.oʊ.m 1
no n.oʊ 1
pool p.u.l 1
probably p.ɹ.ɑ.b.ə.b.l.i 2
stay s.t.eɪ 1
the ð.ə 1
to t.u 2
us ʌ.s 1
with w.ɪ.θ 1

…where the words “going,” “to,” and “probably” each have multiple variants associated with them (see Viewing Pronunciation Variants: for more on how to view these). (Note that to achieve this result, you would indicate in the Parsing Parameters that both lines 2 and 3 are “Transcription” lines, but that line 2 is associated with the lexical item while line 3 is allowed to vary within lexical items.)

A similar method works for creating pronunciation variants from TextGrid files. As in the interlinear gloss files, you would have three tiers in a TextGrid; one with spelling, one with canonical pronunciations; and one with the specific pronunciations used in particular instances. The Parsing Parameters would be filled in similarly.

Note that the canonical pronunciations are in fact optional; it is possible to simply associate pronunciation variants with spelling forms (though this may limit some of the functionality of searching and some analyses).

Viewing Pronunciation Variants:

If a corpus has pronunciation variants, you can view these by right-clicking on any word in the corpus and selecting “List pronunciation variants.” A new dialogue box will pop up that shows the individual pronunciation variants that occur in the corpus for that word, along with their token frequencies. (See also Exporting Pronunciation Variants: for information about how to save these to a .txt file for use outside of PCT.)

_images/pronunciationvariant.png

Options for Pronunciation Variants:

There are four basic options in PCT for dealing with pronunciation variants, each of which is described below. In all cases, the way that PCT handles them is to create a version of the corpus that is set up with the selected option; analysis functions are then applied as normal. Thus, each time that a non-canonical approach is used, there will be a slight delay in processing time while the alternative corpus structure is set up.

  1. Canonical forms: The first option is for PCT to use only the canonical forms in analyses. This is the default and the option that is usually reported in the literature. For many corpora, only the canonical pronunciation is available anyway, and will be the only option. In corpora with pronunciation variants, this option is available only if there is a form that is known by PCT to be the canonical pronunciation (see Creating Pronunciation Variants:). Note that the token frequency values are summed across all variants.

    As an example, the canonical form for the word “cat” is [kæt]; the canonical form for the word “probably” is [pɹɑbəbli]. A fragment of the corpus would be as follows:

    Spelling Transcription Type frequency Token frequency
    cat k.æ.t 1 6
    probably p.ɹ.ɑ.b.ə.b.l.i 1 290
  2. Most frequent forms: Alternatively, PCT can use only the most frequent variant of each lexical item in analyses. This option puts priority on forms as they are actually used most often in the corpus. If there are two or more forms that have equal frequencies, and one of them is the canonical form, then PCT will fall back on the canonical form, if one is available. If no canonical form is available or if it is not one of the forms that is tied for being most frequent, then the longest of the most frequent forms will be chosen (on the assumption that this will be closest to the canonical form). If there is a tie in terms of frequencies AND a tie in terms of the lengths of the tied forms, then PCT will simply use the variant that is first alphabetically.

    As an example, the most frequent form of the word “probably” in the Buckeye corpus is [pɹɑbli]; 66 of the 290 tokens of the word have this form (whereas only 50 are the canonical pronunciation). Similarly, the most frequent form for the word “cat” is [kæʔ]; 3 of the six tokens of “cat” have this pronunciation. Thus, searches and analyses using the most frequent forms would use these transcriptions instead. The token frequency values are again combined across all variants.

    A fragment of the corpus would be as follows:

    Spelling Transcription Type frequency Token frequency
    cat k.æ.ʔ 1 6
    probably p.ɹ.ɑ.b.l.i 1 290
  3. Each word token separately: The third option is for PCT to treat each pronunciation variant as its own separate lexical entry. This allows all variants to be considered, regardless of canonical-ness or frequency. At the same time, it will somewhat artificially inflate the number of occurrences of segments that relatively stably occur in words that otherwise have lots of variation. For example, there are 74 different pronunciation variants of the word “probably” in the Buckeye corpus; 73 of these begin with [p] (one, [frai], begins with [f]). Thus, while this method is useful for seeing the range of variability elsewhere in the word, it will make word-initial [p] seem much more relatively frequent than it actually is. It allows every pronunciation variant to count equally as far as word types are concerned. Token frequencies for each individual variant are used, or each variant is assigned a frequency of 1 if type frequencies are used.

    A fragment of the corpus would be as follows:

    Spelling Transcription Type frequency Token frequency
    cat k.æ.t 1 2
    cat k.æ.ʔ 1 3
    cat k.æ.ɾ 1 1
    probably p.ɹ.ɑ.b.ə.b.l.i 1 50
    probably p.ɹ.ɑ.b.l.i 1 66
    probably p.ɹ.ɑ.l.i 1 35

    … (not all variants of the word “probably” are shown)

  4. Weight each word types by the frequency of each variant: The fourth option is for PCT to weight each variant’s frequency by the overall token frequency (if using token frequency) or by the number of variants (if using type frequency).

    As an example, the word “probably” has 74 variants in the Buckeye corpus. The most frequent, [pɹɑbli], occurs 66 times out of the 290 tokens. 66/290 = 0.2276. So, there would be a lexical entry in the corpus for [pɹɑbli], with a type frequency of 0.2276 (instead of 1). Similarly, the canonical pronunciation, [pɹɑbəbli], occurs with a relative frequency of 50/290 = 0.1724, so that would be the type frequency for its lexical entry. Thus, the total type frequency across all variants of a single lexical item sum to 1. The token frequencies match the original numbers.

    A fragment of the corpus would be as follows:

    Spelling Transcription Type frequency Token frequency
    cat k.æ.t 0.333 2
    cat k.æ.ʔ 0.5 3
    cat k.æ.ɾ 0.167 1
    probably p.ɹ.ɑ.b.ə.b.l.i 0.172 50
    probably p.ɹ.ɑ.b.l.i 0.228 66
    probably p.ɹ.ɑ.l.i 0.121 35

    … (not all variants of the word “probably” are shown)

Exporting Pronunciation Variants:

It is possible to export pronunciation variants with a corpus for easy reference or use outside of PCT. General information about exporting a corpus can be found in Saving and exporting a corpus or feature file. The basic procedure is to go to “File” / “Export corpus as text file” and enter the file name and location and the column and transcription delimiters.

PCT provides three options for exporting pronunciation variants. They can simply be excluded entirely (by selecting “Do not include”); the resulting file will have only the canonical pronunciations, assuming the corpus contains these. The following is an example of the resulting single line of the output file from the Buckeye corpus for the word “probably”:

Spelling Transcription Frequency
probably p.r.aa.b.ah.b.l.iy 290

Alternatively, pronunciation variants can be included in either of two formats. Selecting “Include in each word’s line” will organize the output by lexical item, with exactly one line per item. Pronunciation variants of that item will be listed at the end of the line. Here’s an example of the single line that results for the word “probably” in this version of the export of the Buckeye corpus:

Spelling Transcription Frequency Variants
probably p.r.aa.b.ah.b.l.iy 290 p.r.ah.eh, p.r.aa.b.eh.b.l.ey, p.aa.b.l.ih, f.r.ay, p.r.eh.ih, p.r.aa.b.l.uh, p.ah.r.eh, p.r.aa.b.b.l.iy, p.r.ah.b.l.ah, p.r.aw.b.w.iy, p.r.aw.b.l.iy, p.r.aa.b.ah.b.l.ey, p.r.aa.w.ah.v.w.iy, p.r.aa.ey, p.r.aa.b.ah.b.l, p.r.aa.b.el.ih, p.r.aa.b.w.iy.jh, p.p.r.aa.b.l.iy, p.r.aa.b, p.r.ah.ay, p.r.ah.b.l.ih, p.r.aa.iy.m, p.r.aa.b.uh.b.l.ah, p.aa.b.ow.b.l.iy, p.er.r.eh.ih, p.aa.b.ow.l.iy, p.r.ah.b.w.iy, p.r.aa.b.ow.b.l.ey, p.r.aa.b.ah.b.l.ih, p.r.aa.v.iy, p.r.ah.ey, p.aa.b.ih, p.aa.ih.ih, p.r.aa.r.iy, p.r.aa.l.uw, p.r.aa.b.r.ih, p.ah.b.l.iy, p.r.ao.b.ih, p.ah.l.ih, p.aa.r, p.r.aa.w.iy, p.r.ao.ey, p.r.ow.iy, p.aa.l.iy, p.r.ah.b.uh.b.l.iy, p.r.aa.ah.b.l.iy, p.r.aa.l.eh, p.r.aa.ih, p.r.aa.b.ow.b.l.iy, p.r.ah.l.ih, p.r.ah.b.iy, p.r.aa.b.ih, p.r.aa.el.iy, p.r.aa.b.el.b.l.iy, p.aa.b.el.b.l.iy, p.r.ah.iy, p.aa.ih, p.aa.b.l.iy, p.r.aa, p.r.ah, p.r.aa.v.l.iy, p.r.aa.b.uh.b.l.iy, p.r.aa.b.el.iy, p.r.aa.l.ih, p.r.aa.eh, p.r.ah.l.iy, p.r.ah.b.l.iy, p.r.aa.b.l.ih, p.r.aa.iy, p.r.aa.b.iy, p.r.ay, p.r.aa.l.iy, p.r.aa.b.ah.b.l.iy, p.r.aa.b.l.iy

The other format for exporting pronunciation variants, “Have a line for each variant,” will put each different variant on a separate line in the exported corpus. Each will also include the spelling and canonical transcription (if available). This version also lists the frequency with which each different variant occurs in the corpus. Here’s an example of the 74 lines that result for the word “probably” in this version of the export of the Buckeye corpus:

Spelling Transcription Frequency Token_Transcription Token_Frequency
probably p.r.aa.b.ah.b.l.iy 290 p.r.ah.eh 1
probably p.r.aa.b.ah.b.l.iy 290 p.r.aa.b.eh.b.l.ey 1
probably p.r.aa.b.ah.b.l.iy 290 p.aa.b.l.ih 1
probably p.r.aa.b.ah.b.l.iy 290 p.r.aa.b.l.iy 66
probably p.r.aa.b.ah.b.l.iy 290 p.r.aa.ah.b.l.iy 2
probably p.r.aa.b.ah.b.l.iy 290 p.r.aa.l.eh 2
probably p.r.aa.b.ah.b.l.iy 290 p.r.aa.l.ih 4
probably p.r.aa.b.ah.b.l.iy 290 f.r.ay 1
probably p.r.aa.b.ah.b.l.iy 290 p.r.aa.ih 2
probably p.r.aa.b.ah.b.l.iy 290 p.r.eh.ih 1
probably p.r.aa.b.ah.b.l.iy 290 p.r.aa.b.l.uh 1
probably p.r.aa.b.ah.b.l.iy 290 p.ah.r.eh 1
probably p.r.aa.b.ah.b.l.iy 290 p.r.aa.b.ow.b.l.iy 2
probably p.r.aa.b.ah.b.l.iy 290 p.r.aa.b.b.l.iy 1
probably p.r.aa.b.ah.b.l.iy 290 p.r.ah.b.l.ah 1
probably p.r.aa.b.ah.b.l.iy 290 p.r.aw.b.w.iy 1
probably p.r.aa.b.ah.b.l.iy 290 p.r.aw.b.l.iy 1
probably p.r.aa.b.ah.b.l.iy 290 p.r.aa.b.ah.b.l.ey 1
probably p.r.aa.b.ah.b.l.iy 290 p.r.aa.eh 4
probably p.r.aa.b.ah.b.l.iy 290 p.r.ah.l.ih 2
probably p.r.aa.b.ah.b.l.iy 290 p.r.ah.l.iy 4
probably p.r.aa.b.ah.b.l.iy 290 p.r.ah 3
probably p.r.aa.b.ah.b.l.iy 290 p.r.aa.w.ah.v.w.iy 1
probably p.r.aa.b.ah.b.l.iy 290 p.r.aa.ey 1
probably p.r.aa.b.ah.b.l.iy 290 p.r.aa.v.l.iy 3
probably p.r.aa.b.ah.b.l.iy 290 p.r.aa.b.ah.b.l 1
probably p.r.aa.b.ah.b.l.iy 290 p.r.aa.b.el.ih 1
probably p.r.aa.b.ah.b.l.iy 290 p.r.ah.b.iy 2
probably p.r.aa.b.ah.b.l.iy 290 p.r.aa.b.w.iy.jh 1
probably p.r.aa.b.ah.b.l.iy 290 p.p.r.aa.b.l.iy 1
probably p.r.aa.b.ah.b.l.iy 290 p.r.aa.b 1
probably p.r.aa.b.ah.b.l.iy 290 p.r.aa.b.uh.b.l.iy 3
probably p.r.aa.b.ah.b.l.iy 290 p.r.aa.b.ih 2
probably p.r.aa.b.ah.b.l.iy 290 p.r.ah.ay 1
probably p.r.aa.b.ah.b.l.iy 290 p.r.ah.b.l.ih 1
probably p.r.aa.b.ah.b.l.iy 290 p.r.aa.iy.m 1
probably p.r.aa.b.ah.b.l.iy 290 p.r.aa.el.iy 2
probably p.r.aa.b.ah.b.l.iy 290 p.r.aa.b.ah.b.l.iy 50
probably p.r.aa.b.ah.b.l.iy 290 p.r.aa.iy 6
probably p.r.aa.b.ah.b.l.iy 290 p.r.aa.b.uh.b.l.ah 1
probably p.r.aa.b.ah.b.l.iy 290 p.aa.b.ow.b.l.iy 1
probably p.r.aa.b.ah.b.l.iy 290 p.er.r.eh.ih 1
probably p.r.aa.b.ah.b.l.iy 290 p.aa.b.ow.l.iy 1
probably p.r.aa.b.ah.b.l.iy 290 p.r.aa.b.l.ih 5
probably p.r.aa.b.ah.b.l.iy 290 p.r.aa.b.iy 11
probably p.r.aa.b.ah.b.l.iy 290 p.r.ah.b.w.iy 1
probably p.r.aa.b.ah.b.l.iy 290 p.r.aa.b.ow.b.l.ey 1
probably p.r.aa.b.ah.b.l.iy 290 p.r.aa.b.el.b.l.iy 2
probably p.r.aa.b.ah.b.l.iy 290 p.aa.b.el.b.l.iy 2
probably p.r.aa.b.ah.b.l.iy 290 p.r.ah.b.l.iy 4
probably p.r.aa.b.ah.b.l.iy 290 p.r.aa.b.ah.b.l.ih 1
probably p.r.aa.b.ah.b.l.iy 290 p.r.aa.v.iy 1
probably p.r.aa.b.ah.b.l.iy 290 p.r.ah.ey 1
probably p.r.aa.b.ah.b.l.iy 290 p.aa.b.ih 1
probably p.r.aa.b.ah.b.l.iy 290 p.r.ah.iy 2
probably p.r.aa.b.ah.b.l.iy 290 p.aa.ih.ih 1
probably p.r.aa.b.ah.b.l.iy 290 p.r.aa.b.el.iy 3
probably p.r.aa.b.ah.b.l.iy 290 p.r.aa.r.iy 1
probably p.r.aa.b.ah.b.l.iy 290 p.r.aa.l.uw 1
probably p.r.aa.b.ah.b.l.iy 290 p.aa.ih 2
probably p.r.aa.b.ah.b.l.iy 290 p.aa.b.l.iy 2
probably p.r.aa.b.ah.b.l.iy 290 p.r.aa.b.r.ih 1
probably p.r.aa.b.ah.b.l.iy 290 p.ah.b.l.iy 1
probably p.r.aa.b.ah.b.l.iy 290 p.r.ao.b.ih 1
probably p.r.aa.b.ah.b.l.iy 290 p.ah.l.ih 1
probably p.r.aa.b.ah.b.l.iy 290 p.aa.r 1
probably p.r.aa.b.ah.b.l.iy 290 p.r.aa.w.iy 1
probably p.r.aa.b.ah.b.l.iy 290 p.r.ao.ey 1
probably p.r.aa.b.ah.b.l.iy 290 p.r.aa 2
probably p.r.aa.b.ah.b.l.iy 290 p.r.aa.l.iy 35
probably p.r.aa.b.ah.b.l.iy 290 p.r.ow.iy 1
probably p.r.aa.b.ah.b.l.iy 290 p.r.ay 16
probably p.r.aa.b.ah.b.l.iy 290 p.aa.l.iy 1
probably p.r.aa.b.ah.b.l.iy 290 p.r.ah.b.uh.b.l.iy 1