Cuireadh dearadh taighde modhanna measctha leabaithe (CÁINN (cáil)) i bhfeidhm sa saothar seo le hiniúchadh a dhéanamh ar cé acu cur chuige follasach, cur chuige déaduchtach nó cur chuige ionduchtach-follasach, ab éifeachtaí le forbairt a dhéanamh ar léireolas grúpa MFO sa Ghaeilge. Grúpa MFO (N = 75) sa dara bliain den chéim Baitsiléir san Oideachas (BOid) a bhí mar rannpháirtithe sa taighde. Cuireadh cur chuige ionduchtach-follasach i bhfeidhm le dhá ghrúpa agus cur chuige déaduchtach i bhfeidhm le dhá ghrúpa, agus ní raibh aon idirghabháil sa dá rang-ghrúpa eile, a d’fheidhmigh mar ghrúpa cóimheasa sa chuasai-thriail. Roghnaíodh spriocstruchtúir don chlár teagaisc ó anailís ábhair ar earráidí coitianta sa Ghaeilge scríofa ó shampla MFO (N = 80). Mhair an idirghabháil caoga nóiméad sa tseachtain i rith ocht seachtaine sa chéad seimeastar den bhliain acadúil 2015/2016, agus ba í an taighdeoir féin a bhí mar theagascóir ar na grúpaí turgnamhacha. Dearadh trí leagan de thriail ghramadaí le bheith mar réamhthriail (roimh an idirghabháil), iarthriail (díreach i ndiaidh na hidirghabhála), agus iarthriail mhoillithe (seacht seachtaine i ndiaidh na hidirghabhála). Léiríonn torthaí cainníochtúla an staidéir tomhas mór éifeachta don dá chur chuige follasacha, le claonadh i dtreo an chur chuige ionduchtach-follasaigh mar an cur chuige is éifeachtaí i gcodanna áirithe den triail. Bailíodh eolas cáilíochtúil ó dhá ghrúpa fócais (n = 12) le léargas a fháil ar dhearcadh na MFO i leith na hidirghabhála. Tugann an t-eolas cáilíochtúil le fios go bhféadfadh leas sa bhreis a bheith ag cur chuige ionduchtach-follasach in oideachas MFO i dtaobh múnlú a dhéanamh ar oideolaíocht a bheadh inmholta don seomra ranga bunscoile. Sonraíonn torthaí an taighde gur chóir cur chuige follasach a chur i bhfeidhm i dteagasc an léireolais do MFO sna hinstitiúidí oideachais, agus gur chóir neart ama a thabhairt dó. Cé nach bhfuil sa léireolas ach cuid amháin den saineolas gairmiúil a theastaíonn ó bhunmhúinteoirí le Gaeilge a theagasc go héifeachtach, áitítear sa staidéar seo gur dlúthchuid dá n-eolas ábhair oideolaíoch é. Eascraíonn moltaí ón staidéar d’oideachas MFO sa Ghaeilge agus do thaighde eile amach anseo. XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX An embedded mixed-methods design (QUAN (qual)) was implemented in this study to investigate which explicit approach, a deductive or an explicit-inductive approach, would be most effective in developing the explicit knowledge of a group of SPTs in Irish. Participants were a group of second-year Bachelor in Education (BEd) students (N = 75). A deductive approach was implemented with two groups, an explicit-inductive approach was implemented with two groups, and there was no intervention with the other two groups, which functioned as a control group in the quasi-experiment. Target structures for the instructional programme were selected from a content analysis of common errors in written Irish from a sample of SPTs (N = 80). The intervention took place for fifty minutes a week, over a period of eight weeks in the first semester of the academic year 2015/ 2016, with the researcher as teacher of the experimental groups. Three versions of a grammar test were designed as pre-test (before the intervention), post-test (immediately after the intervention), and delayed post-test (seven weeks following the intervention). Quantitative results show a large effect size for both explicit approaches, with a tendency towards the explicit-inductive approach as being the most effective approach in certain parts of the test. Qualitative data were gathered from two focus groups (n = 12), to gain an insight into the SPTs’ views regarding the intervention. Qualitative data indicate that an explicit-inductive approach may be particularly beneficial in teacher education to model a pedagogy which would be commendable in the primary school classroom. The results of the research illustrate that an explicit approach should be implemented for the teaching of explicit knowledge to SPT in the institutes of higher education, and that adequate time should be allocated to it. It is argued in this study that although explicit knowledge is only one component of the professional knowledge required by primary teachers to teach Irish effectively, it is an integral part of their pedagogical content knowledge. Recommendations arise from the study for teacher education in Irish and for future research.