This file is used to assign dialogue files to PNPCs in game . The dialogues consist of interactions with main character or between party members.
The first column indicates the name of NPC (death variable).
The second one assigns the DLG file with needed dialogues.
The third one is available only in ToB - assigns DLG file for NPC in ToB.
In BG1 TotS we have:

 2DA V1.0
 NONE
           FILE
KIVAN      BKIVAN
ALORA      BALORA
MINSC      BMINSC
DYNAHEIR   BDYNAH
YESLICK    BYESLI
CORAN      BCORAN
AJANTIS    BAJANT
KHALID     BKHALI
JAHEIRA    BJAHEI
GARRICK    BGARRI
SAFANA     BSAFAN
FALDORN    BFALDO
BRANWEN    BBRANW
QUAYLE     BQUAYL
XAN        BXANNN
SKIE       BSKIE
ELDOTH     BELDOT
XZAR       BXZAR
MONTARON   BMONTA
TIAX       BTIAX
KAGAIN     BKAGAI
SHARTEEL   BSHART
EDWIN      BEDWIN
VICONIA    BVICON