The lockText/unlockText have been moved from Ext.grid.header.Container to Ext.grid.Lockable,but the js under extnet/local/ have not been modified.
So, I have to modify the js by myself.
Ext.define("Ext.locale.[my Culture ID].grid.Lockable", {
        override: "Ext.grid.Lockable",
        unlockText: "my unlocktext",
        lockText: "my locktext"
    });