labels as words

[MarcoP]

Here is an additional information about qo- (not really new in itself, but possibly new in this form). 

This is a histogram of prefixes (occurrences of words are counted multiple times):
the green bar is the percentage of words staring with that prefix 
the red bar is the percentage of exactly repeating words

About 30% of the exactly repeating words start with qo-  (e.g. qokedy.qokedy, qokain.qokain)
About 15% of all words start with qo-

The stats on unique words and repeating pairs are similar:
20% of unique repeating pairs start with qo-
9% of unique words start with qo-

To summarize, this are some peculiarities of qo- (and the corresponding o- behavior):

1. very rare in labels (while o- is common)
   
2. almost absent in first words of paragraphs (o- is also rare)
   
3. common in exactly repeating word pairs (o- is neutral)
   

This is not directly related with labels, but it's possible that there are reasons that explain why qo- is rare in labels and frequently repeated.
1 and 2 could be explained by q- needing a "left context" (i.e. an immediately preceding word).
3 evidently must have some other explanation.