Stress
The diagnostics, non-separability and integrity, establish that hot dog (the edible kind) is a compound. If the hot dog you are eating is hotter than mine, you wouldn’t say that you were eating a *hotter dog or a *very hot dog. Given this fact, compare the pronunciation of the sequence hot dogs in the following two sentences:
(9) We ate two hot dogs each.
The hot dogs ran for the lake.
In the first sentence, the main stress in hot dog is on hot. In a neutral pronunciation of the second, both hot and dog are stressed. It is also possible to emphasize dogs by stressing it more heavily: The hot dógs ran for the lake – hot dogs, not hot children, or canines, not frankfurters. These two examples suggest that stress can also be used as a diagnostic for whether or not a sequence of words is a compound – compounds are normally stressed on their first component in English, while phrases are normally stressed on their last element. Take care in applying this diagnostic, however. As many linguists have noted, some compounds like kitchen sink and apple pie are stressed like phrases (see Giegerich 2004 for discussion and analysis), and sometimes people’s pronunciation of compounds differs, as with ginger ale, which some people pronounce gínger ale, and others ginger ále.
