These solid wooden grammar symbols — the full set of geometric shapes corresponding to each part of speech — are the three-dimensional counterpart to the flat grammar symbol cards used in Montessori language work, typically introduced in lower elementary around ages 6–9. Having solid symbols allows children to physically place them above words and phrases during sentence analysis, reinforcing the grammar hierarchy in a way that engages the hands alongside the mind. They are especially valuable for children who need the additional kinesthetic layer to internalize abstract grammatical relationships.