The global aim of the present research paper is an attempt to reach a threshold level of the learning of a foreign language (English) through the development of vocabulary. Observing the very limited rate of use of English in the Algerian community, English as Foreign Language (EFL) students, actually, need to progress in the mastery of that language by reading and/or listening to texts or messages intensively. To achieve this goal, subsequent procedures should take place by giving the foreign language a rather more appreciable position in the community such as the one held by a second language. To be down-to-earth, a brief survey on the linguistic situation in Algeria is exposed where neat clarification of second-foreign language status in the community is laid out to show that the more a (foreign) language is explicitly exposed in its manifold forms, the more are learners, in that community, likely to acquire it as a second language. However, the assumption of presenting the receptive skills (reading and listening) as the most appropriate means for the growth of foreign language vocabulary is supported by Krashen’s input theory where any input to be understood, should come at EFL learners’ capacity to read/listen and decode easily the meaning. In due course, First year EFL students have been subject to a language proficiency test-‘a pre-test then a post-test’. This typical experimental design is an intervention study which contains two groups: ‘the treatment or experimental’ group which receives the treatment, or which is exposed to some special conditions of intensifying vocabulary learning through a varied, comprehensible input; and a second group of EFL learners- the control group- whose role is to provide a baseline. The findings showed better scores among the experimental group compared to the other group. Actually, the results proved the adequacy of the adopted theory.