diff --git a/src/strings.cpp b/src/strings.cpp
--- a/src/strings.cpp
+++ b/src/strings.cpp
@@ -35,8 +35,8 @@
 #include "table/strings.h"
 #include "table/control_codes.h"
 
-DynamicLanguages _dynlang;
-uint64 _decode_parameters[20];
+DynamicLanguages _dynlang;     ///< Language information of the program.
+uint64 _decode_parameters[20]; ///< Global array of string parameters. To access, use #SetDParam.
 
 static char *StationGetSpecialString(char *buff, int x, const char *last);
 static char *GetSpecialTownNameString(char *buff, int ind, uint32 seed, const char *last);
@@ -171,6 +171,10 @@ void SetDParamStr(uint n, const char *st
 	SetDParam(n, (uint64)(size_t)str);
 }
 
+/**
+ * Shift the string parameters in the global string parameter array by \a amount positions, making room at the beginning.
+ * @param amount Number of positions to shift.
+ */
 void InjectDParam(uint amount)
 {
 	assert((uint)amount < lengthof(_decode_parameters));