Script commands are built in and impossible to modify.
However, the text they use can be changed if using the off-line editor - this is how the language support works. Copy the ContinueLabel template into your game (show all library elements at the bottom left; search for ContinueLabel at the top left; click Copy at the top right). Type your text into the box.
In code view, your game will now start like this:
<asl version="550">
<include ref="English.aslx" />
<include ref="Core.aslx" />
<template name="ContinueLabel">Press any key to continue...</template>
<game name= ...