Sure, this may be a dialogue, written in normal-folks language, between a husband and a wife, but that doesn't mean Frost didn't flex his metrical muscles in "Home Burial."
But Frost never liked to keep things simple, so he shakes it up here and there with some magical metrical variation. Take, for example, lines 31 and 32:
"But the child's mound — —"
"Don't, don't, don't, don't' she cried."
Frost breaks up the complete line of iambic pentameter into two lines of dialogue (but he indents the woman's line, so we'll be sure to connect the meters together). Squish them together and you get ten syllables. But we definitely don't have just five stresses in this line.
In the first half, we have three. And then, each instance of the word "don't" in the second line is a strong stressed syllable, as well as the word "cried." That makes for eight—count 'em—stresses in one iambic pentameter line.
Why pack in so many stresses? Well, this is one of the most intense and urgent moments in the poem. We have finally found out what's really coming between this fighting couple, and the poet is packing the meter with stress to show us that these two are under a lot of—you guessed it—stress.
If you're feeling dramatic, you might try reading this poem aloud with a friend (one can play the woman, the other her husband). This might help you spot the places where Frost is straying from the daDUM rhythm of iambic pentameter. And we think you'll find that in the places where he's shaking things up, he's doing so for a reason. Frost was a metrical master, and he knew how to make meter make meaning.