It is known that the north-eastern part of Jiang-Su Province, including Lian-Yun-Gang (連雲港) city, Gan-Yu (赣榆) prefecture, Dong-Hai (東海) prefecture and their surrounding areas, is a boundary region of the two major dialects within the Northern Mandarin area. The language spoken in the northern part of this region shares a number of features with Jiao-Dong (胶東) dialect in Shan-Dong (山東) peninsula. The language in the southern region, on the other hands, is one of the varieties of Jiang-Huai (江淮) dialect.
Three linguistic maps are shown and each of them typically represents the linguistic situation of this region. Relatively older types of lexical contrasts between northern and southern region are presumed in each map;
蜓蜓/蜻蜻 (Map I, "dragonfly")
發瘧子/打半日子 (Map II, "to get a malaria desease")
七七/蛐蛐 (Map III, "cricket")
Three phonological isolines are observed in Map I and II, and their concerns with the isoglosses are inferred.
What is of more interest in these maps is that the older forms are innovated through the linguistic creativity of the people, which reveales itself in the "motivation of the linguistic sign" (the term proposed by De Sassure), i.e. the non-arbitriness of the linguistic sign. In Map I, "dragonfly" is prefixed a surname "官" (or "冠"), which expresses a vivid image of a dragonfly. In Map II, the innovated form "半月子" is created by the contact of northern and southern forms; "瘧子" and "半日子". The homophony of "瘧" and "月" is pointed out as an intermediary of the innovation. In Map III, "cricket" is given a nick-name "八狗子" ("pug-dog"), which may originally come from the onomatopoeia "七七" (homophonous with "seven-seven"). It is assumed that the easy association of the number "seven" to "eight", as well as the folketymology "July" to "Autumn", enables the people to associate "cricket" with "pug-dog". A celebrated form "慶" in the southern region, on the other hands, is created maybe due to the evasion of somewhat unauspicious association of the onomatopoeia with "the forty-ninth day".
It should be noted that the innovations mentioned above chiefly took place in the western part of this region (Dong-Hai pref. and around). That is to say, if the words in the north move to the south, as well as the other way around, they generally pass through the western region, not directly through Lian-Yun-Gang city, where the southern type dialect is rigidly rooted. Further considerations should be made from the extra-linguistic aspects, like history and culture.