[en] Excitation energies of ²⁸Si levels have been measured with the ²⁷Al(p,γ)²⁸Si reaction; the reaction energy is Q = 11584.5 +- 0.4 keV. The width of the semi-bound level at Esub(x) = 11.45 MeV has been determined as GAMMA = 9 +- 2 eV in a ²⁸Si(γ,γ)²⁸Si resonant absorption experiment; a ²⁷Al(p,γ)²⁸Si resonance provided γ-rays of the appropriate energy. Of 33 resonances observed in the ²⁴Mg(α,γ)²⁸Si reaction (Esub(α) = 1.5 - 3.8 MeV), energies, strengths and γ-ray decay have been measured; six of these resonances had not been reported previously. Gamma-ray angular distribution measurements at three resonances yield the resonance Jsup(Λ) values and the mixing ratios of the strongest transitions involved in the decay. A Jsup(π) = 3⁺, T = 1 assignment to the 10.38 MeV level follows from considerations based on the observed transition strengths. The arguments on which T-assignments can be based are critically reviewed. These arguments are used to assign T = 1 character to 19 states in ²⁸Si