Contar la cantidad de veces que una palabra aparece en BigQuery columna

Trate de abajo enfoque simple

with blacklist as (
  select 'with' word union all 
  select 'that' union all
  select 'add more as you see needed'
)
select lower(word) word, count(*) frequency
from data, unnest(regexp_extract_all(col, r'[\w]*')) word
where length(word) > 3  
and word not in (select word from blacklist)
group by word
order by frequency desc