One can’t define “Chasidic” based on language or fashion in clothes. While one can choose to dress like other hasidim, that is constantly changing, as are all fashions. Chasidim are more likely to speak Yiddish than other Jews, but it is a correlation not a hard and fast rule.
For Ashkenazim, using Nusach Sfard (a.k.a. Nusach Ari’zel) is a good indication, but many people daven their family’s nusach, so all this may indicate that an ancestor was chasidic, or not. Regarding kabalah as something important that should affect daily life is a good sign, except that unless a Chasid is a Ben Torah he won’t know the sources of his minhagim, and non-hasidim also have many minhagim based on kaballah only they don’t emphasize it. Favorably regarding the Baal Shem Tov (and other early Hasidim) is a strong indicator, since the yeshiva world traditionally had a negative view of them. Regarding a “Rebbe” as the Gadol ha-Dor is a big factor, but some such as the Satmar Rebbe were leaders of a broader community that including Misnagdim who shared his political views. Having a “rebbe” is very hasidic, but many yeshivish people treat their Rosh Yeshiva in the same way.
And one could argue that the difference between Hasidic and non-Hasidic is largely historical, and in the future the major “line” within the frum community will be based on zionist/non-zionist or perhaps American/Israeli, and that Hasidic/Misnagdid distinctions are really a relic from the 19th century.