Here is a small example of how to load all the labels of a particular label file, in a particular language. It takes about 6-8 seconds on my developer box to load the 122190 label from SYS.

public static void main(Args _args)
info ("Starting");

ClrObject labels = new ClrObject("System.Collections.Generic.Dictionary`2[System.String,System.String]");

labels = Microsoft.Dynamics.Ax.Xpp.LabelHelper::GetAllLabels('SYS', System.Globalization.CultureInfo::CurrentCulture);

ClrObject labelsEnumerator = labels.GetEnumerator();
ClrObject keyValuePair = labelsEnumerator.get_Current();

var currentlabelId = keyValuePair.get_Key();
var currentTxt = keyValuePair.get_Value();
info ("Done");