Speaker History records are structured around a major category (Cnn), a type (sub-category, Ynn) and then a level (Lnn), followed by start (Bnn) and end years (Enn) for each recorded event. These may be interpreted using the following table.
|singing||type||hours / week|
|language||name||1 = not fluent 2 = moderately fluent 3 = fluent|
|education||level||not used (may contain institution name)|
|smoking||type||number or hours/week|
|vocal_stress||type||hours / week|
NOTE: The start year (Bnn) and end year (Enn) are given as a four digit year > 1000.
If Bnn = 0 or blank and Enn < 1000 then Enn = the number of years