In some ways, this poem is a primer in the rural dialect of nineteenth-century England. 'Melia's friend uses all kinds of bizarre phrases, from "spudding up docks" and "barton," to "megrims" and "sock." While the presence of country language in this poem makes the speaker seem more authentic (more legit), they are also Hardy's way of signaling the class differences between the two women. 'Melia no longer uses words like "megrims" because she has moved up the social food chain, even as her friend hasn't. But then again, 'Melia is ruined too, so maybe it's not such a bad thing.
Line 6: "Spudding up docks" means to dig up weeds. The phrase gives these lines a little bit of rural flavor, reminds us of 'Melia's former occupation, and symbolizes her friend's current social status.
Line 9: "Barton" (farm) is just like "spudding up docks" in line 6. It is a dialect word that symbolizes 'Melia's friend's social status, but also 'Melia's former residence and life.
Line 10: These bizarre spellings ("'thik oon'" and 'theäs oon'") are Hardy's way of capturing the accent of rural England. 'Melia used to speak this way, but has somehow managed to get rid of that defining characteristic of country laborers.
Lines 18-19: "Megrims" is a funny word that means "migraine," while "sock" means to sigh loudly or groan or grumble, As with all those other words ("spudding," "barton," etc.), they symbolize 'Melia's friend's social status. They also imply that country life is full of pain, while a "ruined" life in the city is the exact opposite.