Table 4.

Children’s Classroom Language Production: Associations with Child-Level Characteristics.

Model outcome	Model parameter	Fixed effects
		B	SE	t-value	p	95% CI	d
Mean child vocalization duration	Cohort 1 vs. Cohort 2	85.38	23.19	3.68	<0.001	41.64, 129.45	1.05
	Teacher vocalization duration	0.10	0.05	1.92	0.057	−0.002, 0.21	0.34
	HL vs. TH	−41.87	18.41	−2.28	0.030	−76.73, −6.99	−0.83
	Time since start of school year	−0.02	0.10	−0.24	0.814	−0.23, 0.18	−0.04
	Interaction between cohort and teacher vocalization duration	−0.09	0.09	−1.00	0.322	−0.26, 0.08	−0.17
	Interaction between cohort and hearing status	18.95	26.92	0.70	0.488	−31.95, 69.99	0.27
Child rate of vocalizations per minute	Cohort 1 vs. Cohort 2	0.83	0.54	1.52	0.132	−0.20, 1.86	0.36
	Teacher word count rate	0.02	0.01	1.44	0.153	−0.007, 0.05	0.25
	HL vs. TH	0.30	0.40	0.74	0.466	−0.47, 1.06	0.25
	Time since start of school year	0.006	0.003	1.92	0.057	−0.00001, 0.01	0.32
	Interaction between cohort and teacher word count rate	0.07	0.03	2.52	0.013	0.02, 0.12	0.44
	Interaction between cohort and hearing status	−1.21	0.58	−2.09	0.046	−2.31, −0.11	−0.77
Child phonemic diversity	Cohort 1 vs. Cohort 2	0.06	0.06	0.84	0.260	−0.13, 0.51	0.34
	Teacher phonemic diversity	0.19	0.17	1.14	0.404	−0.07, 0.17	0.14
	HL vs. TH	0.19	0.14	1.39	0.174	−0.07, 0.46	0.47
	Time since start of school year	0.001	0.0006	1.79	0.076	−0.00009, 0.002	0.30
	Interaction between cohort and teacher phonemic diversity	0.12	0.09	1.26	0.210	−0.06, 0.30	0.22
	Interaction between cohort and hearing status	0.07	0.21	0.31	0.756	−0.33, 0.46	0.11

The table reports linear mixed effects models. Children observed before COVID-19 (Cohort 1) served as the reference in cohort contrasts. Children with hearing loss (HL) served as the reference group for hearing status contrasts. Time since start of school year was measured in days and served as a cohort-specific, time-varying predictor of teacher speech. Random intercept of subject: Child duration (SD = 30.09, ${\sigma }^2$=905.60), Child rate of vocalizations per minute (SD = 0.51, ${\sigma }^2$=0.26), and Child phonemic diversity (SD = 0.27, ${\sigma }^2$=0.07). Level-1 residuals: Child duration (SD = 53.97, ${\sigma }^2$=2913.00), Child rate of vocalizations per minute (SD = 1.46, ${\sigma }^2$=2.14), and Child phonemic diversity (SD = 0.30, ${\sigma }^2$=0.09).