Table 2.

Results of the linear mixed-effects models for the effects of vowel, condition and vowel × condition on F1, F2, and Duration. The table shows the estimate for the intercept and the coefficients of the model, the standard errors (SE), the degrees of freedom (df), the t-value, and the p-value (Pr(>|t|)); The intercept is vowel /a / in cotton mask condition

			Estimate	SE	df	t value	Pr(>|t|)
F1	(Intercept)		674.95	10.60	238.40	63.696	<2e-16	***
	e		−160.00	14.07	266.00	−11.370	<2e-16	***
	i		−387.05	14.07	266.00	−27.504	<2e-16	***
	o		−178.90	14.07	266.00	−12.713	<2e-16	***
	u		−332.60	14.07	266.00	−23.635	<2e-16	***
	no mask		33.45	14.07	266.00	2.377	0.0182	*
	surgical		26.80	14.07	266.00	1.904	0.0579	.
	e:no mask		−39.95	19.90	266.00	−2.007	0.0457	*
	i:no mask		−24.65	19.90	266.00	−1.239	0.2166
	o:no mask		−36.60	19.90	266.00	−1.839	0.0670	.
	u:no mask		−43.85	19.90	266.00	−2.203	0.0284	*
	e:surgical		−38.70	19.90	266.00	−1.945	0.0529	.
	i:surgical		−23.45	19.90	266.00	−1.178	0.2397
	o:surgical		−44.10	19.90	266.00	−2.216	0.0275	*
	u:surgical		−9.25	19.90	266.00	−0.465	0.6425
F2	(Intercept)		1001.35	20.24	285.00	49.476	< 2e-16	***
	e		521.45	28.62	285.00	18.218	< 2e-16	***
	i		1439.80	28.62	285.00	50.303	< 2e-16	***
	o		−179.30	28.62	285.00	−6.264	1.38e-09	***
	u		−119.45	28.62	285.00	−4.173	3.99e-05	***
	no mask		210.45	28.62	285.00	7.353	2.07e-12	***
	surgical		38.45	28.62	285.00	1.343	0.18023
	e:no mask		42.60	40.48	285.00	1.052	0.29350
	i:no mask		−246.25	40.48	285.00	−6.084	3.78e-09	***
	o:no mask		−197.60	40.48	285.00	−4.882	1.75e-06	***
	u:no mask		−232.35	40.48	285.00	−5.740	2.42e-08	***
	e:surgical		389.60	40.48	285.00	9.625	< 2e-16	***
	i:surgical		59.30	40.48	285.00	1.465	0.14403
	o:surgical		4.85	40.48	285.00	0.120	0.90471
	u:surgical		107.45	40.48	285.00	2.655	0.00839	**
Duration	(Intercept)		190.950	4.323	284.548	44.171	< 2e-16	***
	e		−15.600	6.081	266.000	−2.565	0.0109	*
	i		−42.950	6.081	266.000	−7.063	1.42e-11	***
	o		0.750	6.081	266.000	0.123	0.9019
	u		−39.550	6.081	266.000	−6.504	3.86e-10	***
	no mask		0.650	6.081	266.000	0.107	0.9150
	surgical		15.100	6.081	266.000	2.483	0.0136	*
	e:no mask		−6.950	8.600	266.000	−0.808	0.4197
	i:no mask		−11.900	8.600	266.000	−1.384	0.1676
	o:no mask		−12.800	8.600	266.000	−1.488	0.1378
	u:no mask		−10.900	8.600	266.000	−1.267	0.2061
	e:surgical		4.400	8.600	266.000	0.512	0.6093
	i:surgical		−13.250	8.600	266.000	−1.541	0.1246
	o:surgical		−10.150	8.600	266.000	−1.180	0.2390
	u:surgical		−6.700	8.600	266.000	−0.779	0.4366

Signif. codes: 0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1