Error while conditionally adding columns to an existing dataframe

I am trying to conditionally add a column to a data frame. I have a column named comments which has a text-based on English and German languages. I basically want to detect the language and add a new column with a value en or de depending on the translation.

library(googleLanguageR)
df$language <- ifelse(df$comments %>% 
                           gl_translate_detect() %>% 
                           pull(language) == "en","en", "de"
                         )

However, I get

Error: NA/NaN argument

Expected:

title | comments        | language  
-----------------------------------
A     | I like...       |   en  
B     | I wish...       |   en  
C     | Das ist....     |   de  
C     | Es war...       |   de  
C     | Most of the...  |   en  
...

EDIT: output of gl_translate_detect()

A tibble:1 x 4
confidence  isReliable  language  text
<dbl>         <lgl>     <chr>     <chr>
0.983067      FALSE       de    Dem  ich mich.