Log-means normalization

Normalize vowel formant measurements a log-means normalization procedure as described in Barreda & Nearey (2018). This function is intended to be used within a tidyverse pipeline.

norm_logmeans(
  .df,
  .formant_cols,
  .speaker_col,
  .vowel_col,
  .return = "data",
  i_know_more_than_you = FALSE
)

Arguments

.df

The data frame containing the formant measurements you want to normalize. Formant data must be log transformed! See example code below.

.formant_cols

The (unquoted) name(s) of the column containing the formant measurements.

.speaker_col

The (unquoted) name of the column containing the unique identifiers per speaker.

.vowel_col

The (unquoted) name of the column containing the unique identifiers per vowel

.return

A string. By default, "data", which will returned the your original data with the normalized data appended. If you set this to "params", you'll get a data frame with the normalization paramters for each speakers.

i_know_more_than_you

Logical. The function won't work if you've got data that doesn't look like log10-transformed formant data. If you want to force the function to run anyway, set this to `TRUE`.

Value

The original dataframe with new columns containing the normalized measurements. These new columns have "_norm" appended to the column names.

Details

The data should not be grouped beforehand (e.g. with group_by). The data must be numeric, and there cannot be any NAs.

Note

Thanks to Santiago Barreda for providing most of the code for this function.

References

Barreda, Santiago, and Terrance M. Nearey. 2018. "A Regression Approach to Vowel Normalization for Missing and Unbalanced Data." The Journal of the Acoustical Society of America 144(1): 500–520. https://doi.org/10.1121/1.5047742.

Examples

library(tidyverse)
idaho <- joeysvowels::idahoans
#> Error in loadNamespace(x): there is no package called ‘joeysvowels’

# Basic usage. Note that the data has to be log10-transformed.
idaho %>%
    mutate(F1_log = log10(F1), F2_log = log10(F2)) %>%
    norm_logmeans(.formant_cols = c(F1_log, F2_log),
                  .speaker_col = speaker,
                  .vowel_col = vowel) %>%
    head()
#> Error: object 'idaho' not found

# Return the speaker paramters instead.
idaho %>%
    mutate(F1_log = log10(F1), F2_log = log10(F2)) %>%
    norm_logmeans(.formant_cols = c(F1_log, F2_log),
                  .speaker_col = speaker,
                  .vowel_col = vowel,
                  .return = "params") %>%
    head()
#> Error: object 'idaho' not found

# If you forget to log-transform the data, it'll throw an error.
idaho %>%
    norm_logmeans(.formant_cols = c(F1, F2),
                  .speaker_col = speaker,
                  .vowel_col = vowel)
#> Error: object 'idaho' not found

# But you can force the function to run on non-transformed data if you're sure you know what you're doing.
idaho %>%
    norm_logmeans(.formant_cols = c(F1, F2),
                  .speaker_col = speaker,
                  .vowel_col = vowel,
                  i_know_more_than_you = TRUE) %>%
    head()
#> Error: object 'idaho' not found