The 7Li NMR spectra of the solid solutions between Li3VO4 and Li4TO4 (T=Ge, Si) with different composition were investigated in the range 150-573 K. It was found that the values of 7Li NMR linewidth and spin-lattice relaxation time T1 in γII phase solid solutions are about an order of magnitude less than that of Li4GeO4, Li4SiO4, and Li3VO4 at room temperature. The temperature dependence of the number and the intensity ratio of 7Li NMR quadrupole satellite lines, and the composition dependence of the former were observed. It is suggested that the Li+ ions in samples of γII structural compositions move probably about one order of magnitude faster than that of the three pure compounds. The number of inequivalent sites occupied by the Li+ ions changes with the composition. The occupancy of the Li+ ions in the inequivalent sites changes with the temperature.