When linearity prevails over hierarchy in syntax

Abstract

Hierarchical structure has been cherished as a grammatical universal. We use experimental methods to show where linear order is also a relevant syntactic relation. An identical methodology and design were used across six research sites on South Slavic languages. Experimental results show that in certain configurations, grammatical production can in fact favor linear order over hierarchical structure. However, these findings are limited to coordinate structures and distinct from the kind of production errors found with comparable configurations such as "attraction" errors. The results demonstrate that agreement morphology may be computed in a series of steps, one of which is partly independent from syntactic hierarchy.

Keywords: South Slavic languages; coordinated noun phrases; elicited language production; experimental syntax; syntactic agreement.

Fig. 1.

Hierarchical structure of coordination (–11).

Fig. 2.

Research sites for the South Slavic comparison. Map was created with R’s ggmap package, using Google Maps data.

Fig. 3.

Highest (blue) vs. closest (red) agreement in &Ps. In SV (Left) (preverbal), these two strategies are distinct, whereas in VS (Right) (postverbal) they converge.

Fig. 4.

Rates of hierarchically based (highest) vs. linearly based (closest) agreement for [N&F] and [F&N] conditions, preverbally (n = 180), with average percentage of choice shown per site with SE of mean bars.

Fig. 5.

Production time is significantly correlated with uniformity of productions for the nine gender combinations in the SV condition (where highest and closest agreement diverge), n = 180. In a fully crossed mixed-effects regression, Shannon entropy of responses significantly predicts production time, $\beta$ = 86, t $=$ 4.10, P < 0.0001.

Fig. 6.

Rates of default agreement in SV (preverbal coordination) vs. VS (postverbal coordination) structures. Default agreement is produced significantly more often in SV structures than it is in VS structures (41% vs. 5%, fully crossed and centered logistic mixed-effects linear model, t = 11.72, P < 0.0001).

Fig. 7.

Acceptability ratings for agreement as controlled by the closest (M), default, closest (F or N), highest, or no conjunct (n = 120). Plot is modeled as a fully crossed mixed-effects regression with a five-level Helmert-coded predictor. The combination of default and closest agreement is rated significantly higher than default agreement only. Closest agreement is rated significantly higher than agreement with highest, which in turn is rated higher than the baseline lack of agreement All significant differences marked with * between the relevant columns.

Fig. 8.

Rate of hierarchically based (highest) vs. linearly based (closest) agreement for attraction configurations, with average percentage of choice shown per site with SE of mean bars.

Fig. 9.

Comparison of the relative positions of NP₁ and NP₂ in coordination (Left) vs. attraction (Right) structures.

Fig. 10.

Expected differences between SV and VS conditions if &Ps were flat.

Fig. 11.

Percentage of distal productions (Left) and ratings of distal agreement (Right) for preverbal vs. postverbal structures. Distal agreement in SV is produced significantly more often than it is in VS (14% vs. 3%, fully crossed and centered logistic mixed-effects linear model in lme4, $\beta$ = 1.72, t = 7.01, P < 0.0001). Distal agreement in SV is rated significantly higher than it is in VS (3.02 vs. 2.00, fully crossed and centered mixed-effects linear model in lme4, $\beta$ = 1.02, t = 8.92, P < 0.0001).